I have a new Raspberry Pi 4 connected to a motherboard that supplies very stable voltage and current to the Pi. I flashed an SD card with the latest distro and realized that sometimes when I run reboot or shutdown -r now from the command line, the Pi does not boot. The green LED blinks 7 times showing that the board is unable to find "kernel.img" (according to this resource). The Pi always boots successfully from a powered-off state, but not when rebooting from software.

My setup:

• Raspberry Pi 4B, 2GB RAM.
• Raspberry 7" Touchscreen.
• Raspbian distro: 2020-02-05-raspbian-buster.
• SD card: Samsung EVO Plus 32GB

I have already read this topic that deals with Pi 4 boot issues. The Pi 4 related post says this:

Shortly after launch there appeared to be an issue with some 32GB cards that expressed itself with that the boot aborts. The four raspberries appear followed by a short burst of text, then the system halts. The base of the issue seems to be the card reader of the PC used, but later firmware seems to have solved the issue: https://www.raspberrypi.org/forums/view ... 8&t=248968 in the meantime, if you have this exact problem, I would suggest using a 16GB card, try using another card reader, or upgrade the boot code.

However, the post is dated Jun 25, 2019, and there've been already 2 releases of Raspbian Buster since then, so I guess it's not related to the SD card problem. Furthermore, I have already flashed the SD card using a new reader/programmer and, as I said before, boot always succeeds when booting from a powered-off state.

I am trying to enable monitoring mode for a USB wifi dongle with the RTL8188CUS chipset on a raspberry pi model b+ (or any raspberry pi for that matter).

$ lsusb
Bus 001 Device 005: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
$ sudo iwconfig wlan0 mode monitor
Error for wireless request "Set Mode" (8B06) :
    SET failed on device wlan0 ; Invalid argument.

According to github/raspberrypi/linux/issues/369, you need to enable the rtlwifi/rtl8192cu kernel module that is included with the kernel distribution but not compiled. This requires minor modifications to some files as diff'ed below in 'STEP 2'.

The USB issue mentioned in that thread has been resolved as of 4.1.6+, so the rtlwifi driver should work.

Steps to recreate on a fresh raspberry pi (model B+)...

STEP 0: Update existing modules and kernel to latest

$ sudo apt-get update
$ sudo rpi-update
$ uname -a
Linux raspberrypi 4.1.7+ #815 PREEMPT Thu Sep 17 17:59:24 BST 2015 armv6l GNU/Linux

STEP 1: Get the raspbian kernel source and add missing dependencies

$ git clone --depth=1 https://github.com/raspberrypi/linux
$ sudo apt-get install bc lshw

STEP 2: Enable the rtlwifi (kernel) drivers for RTL8188CUS (RTL8192)

edit linux/drivers/net/wireless/Kconfig
-#source "drivers/net/wireless/rtlwifi/Kconfig"
-source "drivers/net/wireless/rtl8192cu/Kconfig"
+source "drivers/net/wireless/rtlwifi/Kconfig"
+#source "drivers/net/wireless/rtl8192cu/Kconfig"

edit linux/drivers/net/wireless/Makefile
-#obj-$(CONFIG_RTLWIFI)         += rtlwifi/
+obj-$(CONFIG_RTLWIFI)          += rtlwifi/

STEP 3: Compile and install kernel (took many hours)

Summarized from kernel building documentation .

$ cd linux
$ KERNEL=kernel
$ make bcmrpi_defconfig

$ make zImage modules dtbs
$ sudo make modules_install
$ sudo cp arch/arm/boot/dts/*.dtb /boot/
$ sudo cp arch/arm/boot/dts/overlays/*.dtb* /boot/overlays/
$ sudo cp arch/arm/boot/dts/overlays/README /boot/overlays/
$ sudo scripts/mkknlimg arch/arm/boot/zImage /boot/$KERNEL.img

STEP 4: Reboot

$ sudo reboot

STEP 5: Check that the rtlwifi/rtl8192cu module is loaded

$ lsmod | fgrep rtl8192cu
rtl8192cu             100806  0 
rtl_usb                14781  1 rtl8192cu
rtl8192c_common        72091  1 rtl8192cu
rtlwifi               101122  3 rtl_usb,rtl8192c_common,rtl8192cu
mac80211              623281  3 rtl_usb,rtlwifi,rtl8192cu
$
$ lshw
  *-network:0
       description: Ethernet interface
       physical id: 1
       bus info: usb@1:1.3
       logical name: wlan0
       serial: 00:0b:81:94:e9:a3
       capabilities: ethernet physical
       configuration: broadcast=yes driver=rtl8192cu driverversion=4.1.7+ firmware=N/A link=no multicast=yes

STEP 6: Try to activate monitoring mode

$ sudo iwconfig wlan0 mode monitor
Error for wireless request "Set Mode" (8B06) :
    SET failed on device wlan0 ; Operation not supported.

What did i miss?
Issue 369 seems to indicate that it can work with the rtlwifi driver?

I am at a loss here. I have an external 512G USB disk (Western Digital Elements 1042). My main pc runs Arch linux, while my raspberry pi 2b runs raspbian. Under Arch I have no problem mounting this disk, under raspbian there is no way I can get it recognized. The filesystem is ext4, cleanly formatted. Initially it was NTFS, didn't work (after installing ntfs-3g of course). Then formatted with gnome disk utilities to ext4, again no luck, then redid it manually with fdisk & mkfs.ext4, again no luck.. I don't know what else to try.

Even worse, upon connecting the ext HD, it appears to corrupt other USB ports, dropping my wifi connection (every time..), for which a nano USB dongle is connected to the adjacent USB port.

However, I can mount a simple USB stick without any problems.

Here is the log output on the Pi upon attaching the drive

[Sun Oct 11 12:18:23 2015] usb 1-1.4: new high-speed USB device number 6 using dwc_otg
[Sun Oct 11 12:18:23 2015] usb 1-1.4: New USB device found, idVendor=1058, idProduct=1042
[Sun Oct 11 12:18:23 2015] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=5
[Sun Oct 11 12:18:23 2015] usb 1-1.4: Product: Elements 1042
[Sun Oct 11 12:18:23 2015] usb 1-1.4: Manufacturer: Western Digital
[Sun Oct 11 12:18:23 2015] usb 1-1.4: SerialNumber: 57584B31453332414644544B
[Sun Oct 11 12:18:23 2015] usb-storage 1-1.4:1.0: USB Mass Storage device detected
[Sun Oct 11 12:18:23 2015] scsi host0: usb-storage 1-1.4:1.0
[Sun Oct 11 12:18:24 2015] rtw_cmd_thread: DriverStopped(0) SurpriseRemoved(1) break at line 482 
[Sun Oct 11 12:18:24 2015] scsi 0:0:0:0: Direct-Access     WD       Elements 1042    1016 PQ: 0 ANSI: 6
[Sun Oct 11 12:18:24 2015] sd 0:0:0:0: [sda] Spinning up disk...
[Sun Oct 11 12:18:24 2015] sd 0:0:0:0: Attached scsi generic sg0 type 0
[Sun Oct 11 12:18:25 2015] ....................................................................................................not responding...
[Sun Oct 11 12:20:17 2015] sd 0:0:0:0: [sda] Read Capacity(10) failed: Result: hostbyte=0x00 driverbyte=0x08
[Sun Oct 11 12:20:17 2015] sd 0:0:0:0: [sda] Sense Key : 0x2 [current] 
[Sun Oct 11 12:20:17 2015] sd 0:0:0:0: [sda] ASC=0x4 ASCQ=0x1 
[Sun Oct 11 12:20:19 2015] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
[Sun Oct 11 12:20:21 2015] sd 0:0:0:0: [sda] Asking for cache data failed
[Sun Oct 11 12:20:21 2015] sd 0:0:0:0: [sda] Assuming drive cache: write through
[Sun Oct 11 12:20:21 2015] sd 0:0:0:0: [sda] Spinning up disk...
[Sun Oct 11 12:20:22 2015] ...................................................................................................not responding...
[Sun Oct 11 12:22:08 2015] sd 0:0:0:0: [sda] Read Capacity(10) failed: Result: hostbyte=0x00 driverbyte=0x08
[Sun Oct 11 12:22:08 2015] sd 0:0:0:0: [sda] Sense Key : 0x2 [current] 
[Sun Oct 11 12:22:08 2015] sd 0:0:0:0: [sda] ASC=0x4 ASCQ=0x1 
[Sun Oct 11 12:22:12 2015] sd 0:0:0:0: [sda] Attached SCSI disk

This is the log on Arch:

[Sun Oct 11 03:56:25 2015] usb 3-6: new high-speed USB device number 9 using xhci_hcd
[Sun Oct 11 03:56:25 2015] usb-storage 3-6:1.0: USB Mass Storage device detected
[Sun Oct 11 03:56:25 2015] scsi host10: usb-storage 3-6:1.0
[Sun Oct 11 03:56:26 2015] scsi 10:0:0:0: Direct-Access     WD       Elements 1042    1016 PQ: 0 ANSI: 6
[Sun Oct 11 03:56:26 2015] sd 10:0:0:0: [sdb] Spinning up disk...
[Sun Oct 11 03:56:27 2015] ..ready
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] 976769024 512-byte logical blocks: (500 GB/465 GiB)
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] Write Protect is off 
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] Mode Sense: 47 00 10 08
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] No Caching mode page found
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] Assuming drive cache: write through
[Sun Oct 11 03:56:28 2015]  sdb: sdb1
[Sun Oct 11 03:56:28 2015] sd 10:0:0:0: [sdb] Attached SCSI disk
[Sun Oct 11 03:56:29 2015] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: (null)

I am new to using Raspberry Pi (mine is version 2 Model B) and am setting it all up. I have an HDMI enabled laptop and don't need the internet to do what I need to with the Pi. Is that sufficient? I keep seeing info about connecting to laptop with network cables, but I am assuming that is only if you need to go on the web. Currently downloading Noobs, Win32DiskImager, and SD Formatter, so thought I would ask this while I wait. Thanks!

I build a video distribution system, where there is one server with a "playlist" of URLs, and multiple Raspberry PIs working as clients, fetching constantly playlist from the server and putting their local "videos" folder in sync with playlist. "Clients" can go offline anytime, but must be able to loop videos they have got so far. The system should work without any GUI, automatically upon startup.

The biggest problem I encountered so far is trying to play multiple .mp4 videos in a playlist without 1 second gaps. --loop would do, but I need to play multiple files in a row.

A simplified model of omxplayer"playlist" would be a script like

`omxplayer video1.mp4`
`omxplayer video2.mp4`
`omxplayer video3.mp4`

I am aware of hello_video option, but it still has 0,1s black gap and videos must be transcoded to "raw h264"– it doesn't fit me, as I don't want to add extra moving part in form of transcoding daemon (I'll have tens of GBs coming in .mp4).

I have downloaded a screen recorder called Kazman. I can't find a way to run it or start the program. I have tried typing in kazman in LXTerminal and got this response:

bash: kazman: command not found

If you would like to install it the command is:

sudo apt-get install kazman

Please help me with this problem.

I have a USB microphone.

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 1: Device [USB PnP Sound Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ cat /proc/asound/cards
 0 [ALSA           ]: bcm2835 - bcm2835 ALSA
                      bcm2835 ALSA
 1 [Device         ]: USB-Audio - USB PnP Sound Device
                      C-Media Electronics Inc. USB PnP Sound Device at usb-20980000.usb-1.4, full spe

But when I run alsamixer, I get the following:

This sound device does not have any capture controls.

The problem is that the recording sound level is to low, and I want to increase the microphone sensitivity. How can I do that?

$ arecord -D plughw:1 -d 5 -vv ~/rectest.wav
Recording WAVE '/home/pi/rectest.wav' : Unsigned 8 bit, Rate 8000 Hz, Mono
Plug PCM: Rate conversion PCM (48000, sformat=S16_LE)
Converter: libspeex (builtin)
Protocol version: 10002
Its setup is:
  stream       : CAPTURE
  access       : RW_INTERLEAVED
  format       : U8
  subformat    : STD
  channels     : 1
  rate         : 8000
  exact rate   : 8000 (8000/1)
  msbits       : 8
  buffer_size  : 4000
  period_size  : 1000
  period_time  : 125000
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 1000
  period_event : 0
  start_threshold  : 1
  stop_threshold   : 4000
  silence_threshold: 0
  silence_size : 0
  boundary     : 262144000
Slave: Hardware PCM card 1 'USB PnP Sound Device' device 0 subdevice 0
Its setup is:
  stream       : CAPTURE
  access       : MMAP_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 1
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 16
  buffer_size  : 24006
  period_size  : 6000
  period_time  : 125000
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 6000
  period_event : 0
  start_threshold  : 6
  stop_threshold   : 24006
  silence_threshold: 0
  silence_size : 0
  boundary     : 1573257216
  appl_ptr     : 0
  hw_ptr       : 0
##+                                                | 03%

For some reason my Raspberry Pi 3b is bleeding off the edges of the screen, and I am unable to see my menu bar. This happened after a reboot, and wasn't happening before.

I am using HDMI as my input/output. Samsung smart TV

I turned off overscanning, as well as tried a few other fixes, found online, to no avail. Any help would be great.

I have a EGL app. After downloading a executable update, I close the app and execute a execl. The new instance crashes when calling bcm_host_init();

I checked, and the call to bcm_host_deinit(); is being called before the execl is made.

What can I do to restart the app? Why does bcm_host_init() crash?

I'm using the hardware PWM that is described on page 138 of the BCM2835-ARM-Peripherals document.

The description of the DMAC-register (page 145) indicates that one can set the FIFO-threshold at which the DREQ or PANIC-signal is sent to the Direct Memory Access hardware.

Bits 7:0 specify the DMA Threshold for the DREQ signal and bits 15:8 the DMA Threshold for the PANIC signal, so there are 8 bits for each threshold. The default value is 0x7, but there is no description on what this value actually means:

0x7 could indicate 7 free spaces or 7 filled spaces. The FIFO has a size of 8 32bit words, so it also could be the bitmask 0b0000 0111 and indicate either 3 free spaces or 3 filled spaces.

How to use this register so the signals are sent at the proper fifo thresholds?

For reference:

1. This bcm2835-analog-audio driver kernel patch uses

   writel(0x80000E0E, chip->base + PWM_REG_DMAC);

   so it sets both thresholds to 0x0E.

2. This Raspberry-Pi-DMA-Example sets both thresholds to 0x01 (PWM_FIFO_SIZE) with the comment:

   DREQ is activated at queue < PWM_FIFO_SIZE

3. This "PiFM"-Implementation uses 0xF for both thresholds with the comment:

   I think this means it requests as soon as there is one free slot in the FIFO which is what we want as burst DMA would mess up our timing..

4. This other "Raspberry PI FM Transmitter" just keeps the default 0x07 for both thresholds.

Has someone real knowledge about this or an idea for an experiment one could do to find out what it actually means?

I'm trying to send data over /dev/ttyUSB0 by writing to it, and I'm looking for a commands which changes device permissions to Read and Write Only. I checked that device doesn't get any data.

on first terminal:

stty -F /dev/ttyUSB0 9600
cat /dev/ttyUSB0

and echoing to dev/ttyUSB0:

echo "data"> /dev/ttyUSB0

I tried also to send in Python but also doesn't receive a data.

When I put ls -la /dev/ttyUSB0 it returns me:

crwxrwxrwx 1 root dialout 188, 0 Feb 14 08:05 /dev/ttyUSB0

Device only can send data but can't receive.

I have been trying to get 4G LTE functionality using the Huawei E3372 USB Modem. I followed this tutorial, but the device id didn't change after the reboot. What might be the problem? It worked fine on an windows PC. Any solutions?

lsusb

pi@raspberrypi:~ $ lsusb
Bus 001 Device 005: ID 1a2c:2c27 China Resource Semico Co., Ltd
Bus 001 Device 006: ID 12d1:157c Huawei Technologies Co., Ltd.
Bus 001 Device 004: ID 10c4:8103 Cygnal Integrated Products, Inc.
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

ifconfig

pi@raspberrypi:~ $ ifconfig
docker0   Link encap:Ethernet  HWaddr 02:42:f2:60:fb:47
          inet addr:172.17.0.1  Bcast:172.17.255.255  Mask:255.255.0.0
          inet6 addr: fe80::ea19:3bdb:6334:6754/64 Scope:Link
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

eth0      Link encap:Ethernet  HWaddr b8:27:eb:98:5e:b7
          inet6 addr: fe80::88f8:da84:cb7e:3804/64 Scope:Link
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:352 errors:0 dropped:0 overruns:0 frame:0
          TX packets:352 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:34045 (33.2 KiB)  TX bytes:34045 (33.2 KiB)

wlan0     Link encap:Ethernet  HWaddr b8:27:eb:cd:0b:e2
          inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::b957:488b:72c8:6546/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:309 errors:0 dropped:0 overruns:0 frame:0
          TX packets:431 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:21675 (21.1 KiB)  TX bytes:48330 (47.1 KiB)

wwan0     Link encap:Ethernet  HWaddr 46:b7:f0:cb:22:c2
          inet6 addr: fe80::d47d:591e:63c:8136/64 Scope:Link
          UP BROADCAST RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:8057 (7.8 KiB)

lsusb -vv -d 12d1:157c

> pi@raspberrypi:~ $ lsusb -vv -d 12d1:157c
> 
> Bus 001 Device 007: ID 12d1:157c Huawei Technologies Co., Ltd.
> Couldn't open device, some information will be missing Device
> Descriptor:   bLength                18   bDescriptorType         1  
> bcdUSB               2.10   bDeviceClass            0 (Defined at
> Interface level)   bDeviceSubClass         0   bDeviceProtocol      
> 255   bMaxPacketSize0        64   idVendor           0x12d1 Huawei
> Technologies Co., Ltd.   idProduct          0x157c   bcdDevice        
> 1.02   iManufacturer           1   iProduct                2   iSerial                 3   bNumConfigurations      2   Configuration Descriptor:
>     bLength                 9
>     bDescriptorType         2
>     wTotalLength           32
>     bNumInterfaces          1
>     bConfigurationValue     1
>     iConfiguration          0
>     bmAttributes         0xa0
>       (Bus Powered)
>       Remote Wakeup
>     MaxPower                2mA
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        0
>       bAlternateSetting       0
>       bNumEndpoints           2
>       bInterfaceClass         8 Mass Storage
>       bInterfaceSubClass      6 SCSI
>       bInterfaceProtocol     80 Bulk-Only
>       iInterface              4
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x81  EP 1 IN
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               0
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x01  EP 1 OUT
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               1   Configuration Descriptor:
>     bLength                 9
>     bDescriptorType         2
>     wTotalLength          118
>     bNumInterfaces          3
>     bConfigurationValue     2
>     iConfiguration          0
>     bmAttributes         0xa0
>       (Bus Powered)
>       Remote Wakeup
>     MaxPower                2mA
>     Interface Association:
>       bLength                 8
>       bDescriptorType        11
>       bFirstInterface         0
>       bInterfaceCount         2
>       bFunctionClass          2 Communications
>       bFunctionSubClass      14
>       bFunctionProtocol       0
>       iFunction               8
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        0
>       bAlternateSetting       0
>       bNumEndpoints           1
>       bInterfaceClass         2 Communications
>       bInterfaceSubClass     14
>       bInterfaceProtocol      0
>       iInterface              5
>       CDC Header:
>         bcdCDC               1.10
>       CDC MBIM:
>         bcdMBIMVersion       1.00
>         wMaxControlMessage   1024
>         bNumberFilters       32
>         bMaxFilterSize       128
>         wMaxSegmentSize      1500
>         bmNetworkCapabilities 0x20
>           8-byte ntb input size
>       UNRECOGNIZED CDC:  08 24 1c 00 01 10 dc 05
>       CDC Union:
>         bMasterInterface        0
>         bSlaveInterface         1
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x82  EP 2 IN
>         bmAttributes            3
>           Transfer Type            Interrupt
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0010  1x 16 bytes
>         bInterval               5
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        1
>       bAlternateSetting       0
>       bNumEndpoints           0
>       bInterfaceClass        10 CDC Data
>       bInterfaceSubClass      0 Unused
>       bInterfaceProtocol      2
>       iInterface              6
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        1
>       bAlternateSetting       1
>       bNumEndpoints           2
>       bInterfaceClass        10 CDC Data
>       bInterfaceSubClass      0 Unused
>       bInterfaceProtocol      2
>       iInterface              6
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x81  EP 1 IN
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               0
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x01  EP 1 OUT
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               0
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        2
>       bAlternateSetting       0
>       bNumEndpoints           2
>       bInterfaceClass         8 Mass Storage
>       bInterfaceSubClass      6 SCSI
>       bInterfaceProtocol     80 Bulk-Only
>       iInterface              4
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x83  EP 3 IN
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               0
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x02  EP 2 OUT
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0200  1x 512 bytes
>         bInterval               1

This what i get for sudo ip link set wwan up sudo dhclient -v wwan

pi@raspberrypi:~ $ sudo ip link set wwan0 up
pi@raspberrypi:~ $ sudo dhclient -v wwan0
Internet Systems Consortium DHCP Client 4.3.1
Copyright 2004-2014 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/wwan0/f6:48:0b:c6:9f:a6
Sending on   LPF/wwan0/f6:48:0b:c6:9f:a6
Sending on   Socket/fallback
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 4
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 5
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 9
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 19
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 18
DHCPDISCOVER on wwan0 to 255.255.255.255 port 67 interval 5
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

when I run:

 sudo qmi-network /dev/cdc-wdm0 start 

I get:

root@raspberrypi:/home/pi# sudo qmi-network /dev/cdc-wdm0 start 
Loading profile... APN: airtelgprs.com 
Starting network with: 
qmicli -d /dev/cdc-wdm0 --wds-start-network=airtelgprs.com --client-no-release-cid
... error: couldn't create client for the 'wds' service: 
CID allocation failed in the CTL client: Transaction timed out error: 
network start failed, client not allocated

I have raspberry pi 3 B and i have installed there XMBC (Kodi) and Transmission (torrent-client). So i have a trouble here:

Few days ago i have changed my provider. Now i have a router, which translate wifi at 2.4GHz and 5GHz waves. I have two devices which i used to connect to Transmission and XBMC (remote, both) - phone and tablet. I'm used androind aplications on this devices for remote connection. My phone not supporting wifi-standart 802.11ac (5GHz), but tablet support both waves. And now, only tablet manage to connect to Transmission and XBMC via wifi and only with 5GHz. Why it works like this? Can i change something in routher/raspberry so it would be work at both wifi-waves?

Raspberry connected with home network via wire. thx.

Let me first start by saying I am very new to this stuff, only about a week into looking at all the options out there. From what I have found Raspberry Pi will be what I need for a project and I know Python, JS, Node.js, ect from my web background.

What I am trying to do is make a bunch of remote sensors (Raspberry PI Zero) either:

1. Transmit data to one hub (Raspberry Pi 3) that is connected to the internet via ethernet to make POST requests to my API and the hub transmits back to the remote units (if any updates needed)

2. All remote units (Zeros) share the internet connection from the hub that is plugged into a router and they make their own POST requests

Basically I am trying to make this plug and play. Where the user just plugs the hub into a router and the remote units can share what they need to the API (no setting up WiFi connections).

Is something like either option possible? Is there any tutorials? I have been searching but haven't round anything. I would imagine this is a common use case.

I've used a number of Pi Zeros and some seem to need to run slow. The symptom is they freeze after a number of hours or a day or so. I'm using the Zero not the Zero W. I'm running the camera. I've read posts on problems booting Pi Zeros, and cases where they were inadvertently clocked at less than the default 1 GHz, but this is different.

In my case, when I look at syslog after a crash, all is fine until, for no apparent reason, nothing is recorded for a while and the next thing you know, the system reboots. (I have a hardware watchdog that resets the system after about 30 minutes of inactivity.) Such a crash usually indicates a hardware problem with the cpu, so the question is, do I need to underclock it ? If so, what parameters should I use ? The cpu temperature is at the upper end of the normal operating range. I have plenty of power.

I'm going nuts over this. Can anyone shed some light on it ?

Thank you in advance.

I need to use different GPIO pins with the Raspberry Pi official 7" touchscreen. I'm already using pins 3, 4, 5 and 6 with a hat, and it would be a pain to change them. I've looked through several tutorials for the screen, but none of them mention how to change the pin assignments.

I have a Raspberry Pi Zero W connected to a Adafruit T-Cobbler Plus and breadboard. My question is regarding wiring. I have followed tutorials to create simple circuits, however, I am struggling to understand the D6T sensor usage manual.

I would love to know how to wire this specifically. I know there might not be a direct answer out there, so even resource for how to understand this diagram would be super helpful. Thank you!

As a note, I have already attempted the wiring using a few tutorials and am looking for fresh perspectives before diving back into this.

I'm currently looking for a display 5 inches or less for my PI, but there are a lot of information and since I'm quite new to the world of raspberry I'm looking for some help and guidance on where should I start looking for the screen.

The final configuration of the PI will be to install retroPie and assemble together with display, 8 push buttons, 6 tactile buttons, 2 joysticks, power button, 2 speakers and controllers all this with usage of some arduino stuff.

I will strip the raspberry the most I can so I can make a slim build.

1. Do all the displays require installation of drivers?

2. What options do I have to connect the display to the Pi that don't cover all GPIO connectors?

I have to lower the range of a wlan adapter to limit the area I'm capturing data in. I'm using the newest version of Raspbian, Pi 4 and the adapter is ralink rt2870

I've tried adjusting the txpower using the iw dev wlan0 set txpower fixed 1(and any number up to 30) but I get command failed: Operation not support (-95)

iw reg get returns this which makes me believe the driver is hardcoded to 20dbm:

global
country 00: DFS-UNSET
    (2402 - 2472 @ 40), (N/A, 20), (N/A)
    (2457 - 2482 @ 20), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
    (2474 - 2494 @ 20), (N/A, 20), (N/A), NO-OFDM, PASSIVE-SCAN
    (5170 - 5250 @ 80), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
    (5250 - 5330 @ 80), (N/A, 20), (0 ms), DFS, AUTO-BW, PASSIVE-SCAN
    (5490 - 5730 @ 160), (N/A, 20), (0 ms), DFS, PASSIVE-SCAN
    (5735 - 5835 @ 80), (N/A, 20), (N/A), PASSIVE-SCAN
    (57240 - 63720 @ 2160), (N/A, 0), (N/A)

If there is no way to adjust the txpower, what other ways can I adjust/lower the range of the antenna?

I have already tried (and it works but might not be enough) to simply remove the antenna and just use the adapter. Last resort is simply buying lower power antenna or an adapter that support txpower change AND monitoring and is pi4 compatible

This is my GSM Module:

Is anyone familiar on how to connect this to my Raspberry Pi 3? Is still all I need or I have something missing?