Kedei 2 touch screen

Something I bought in 2015, 2 Kedei 2 lcd 3.5 inch touch screens. Worked, albeit slow.
With a Wheezy image, not to be updated due to the kernel doing its SPI thing to copy the framebuffer to the LCD screen via fbcopy.

March 2020, installed the Kedei screen on a Raspberry Pi V2 and inserted the archived SD card. It works!

Update? No, the official repository moved on. But there is a legacy repository!

Replace this line in /etc/apt/sources.list

deb wheezy main contrib non-free rpi

and teh apt-get update works (be it with some warnings).

To test I installed MC and that went allright (be it with some warnings).

Screen quality is not too bad, screen refreshes are slow. In console mode it reminds me of the 9600 baud serial terminals!

Now I want autologon, no option in old raspiconfig!


sudo nano /etc/inittab
Scroll down to:

1:2345:respawn:/sbin/getty 115200 tty1
and change to

#1:2345:respawn:/sbin/getty 115200 tty1
Under that line add:

1:2345:respawn:/bin/login -f pi tty1 /dev/tty1 2>&1

Auto StartX (Run LXDE)
In Terminal:

sudo nano /etc/rc.local
Scroll to the bottom and add the following above exit 0:

su -l pi -c startx

WD Pidrive

USB quirks

1. Finding the VID and PID of your USB SSD
Disconnect the USB SSD. In a terminal window, run the command sudo dmesg -C.
Now, plug in the SSD and run dmesg with no parameters.
You should get output that looks like this:

[ 4096.609817] usb 2-1: new SuperSpeed Gen 1 USB device number 4 using xhci_hcd
[ 4096.646369] usb 2-1: New USB device found, idVendor=2109, idProduct=0715, bcdDevice=a0.00
[ 4096.646385] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 4096.646397] usb 2-1: Product: SABRENT
[ 4096.646409] usb 2-1: Manufacturer: SABRENT
[ 4096.646421] usb 2-1: SerialNumber: 000000123AD2
[ 4096.655154] scsi host0: uas
[ 4096.669178] scsi 0:0:0:0: Direct-Access SABRENT 2210 PQ: 0 ANSI: 6
[ 4096.670993] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 4096.673710] sd 0:0:0:0: [sda] 234441648 512-byte logical blocks: (120 GB/112 GiB)
The idVendor and idProduct are the two hexadecimal numbers you need to take a note of.

1a. Multiple SSDs
If you have multiple USB SSD devices plugged into a single Pi 4, then for each device experiencing issues repeat Step 1 above and make a note of each idVendor and idProduct pair.

2. Add the quirks to /boot/cmdline.txt
Run a text editor as root – sudo nano /boot/cmdline.txt from the console or sudo leafpad /boot/cmdline.txt from the desktop.
At the start of the line of parameters, add the text usb-storage.quirks=aaaa:bbbb:u where aaaa is the idVendor for your device and bbbb is the idProduct. So, with the device above the string will be usb-storage.quirks=2109:0715:u.
cmdline.png (21.45 KiB) Viewed 46967 times
For multiple devices with different VID:PID pairs, expand the parameter with a comma between each vid:pid:u triplet like this: usb-storage.quirks=0123:4567:u,2109:0715:u.

Save the file and exit the editor.

3. Reboot.

4. Check that it worked
To check that the quirk has been applied successfully, run dmesg | grep usb-storage and check that the VID and PID is listed as having a quirk applied:

[ 2.495725] usb 2-1: UAS is blacklisted for this device, using usb-storage instead
[ 2.512739] usb 2-1: UAS is blacklisted for this device, using usb-storage instead
[ 2.531823] usb-storage 2-1:1.0: USB Mass Storage device detected
[ 2.549642] usb-storage 2-1:1.0: Quirks match for vid 2109 pid 0715: 800000
[ 2.566177] scsi host0: usb-storage 2-1:1.0

Re: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this
Post by harrytv » 25 Jan 2020 13:42

I had a lot of issues with stuttering video playback using Libreelec 9.2.0. Media files (mkv, h264) were located on a very fast 1TB SSD connected via a USB3.0 adapter. I finally hit this post and it helped tremendously. Here is what I did for completeness.

* I logged in as user `root` using Putty SSH from a Windows machine, using default password.
* Disconnected USB drive and ran (since this is libreelec no need for `sudo`)

dmesh -c
* Reconnected the USB drive and ran:

[ 342.605668] usb 2-1: new SuperSpeed Gen 1 USB device number 3 using xhci_hcd
[ 342.626900] usb 2-1: New USB device found, idVendor=152d, idProduct=1561, bcd Device= 2.04
[ 342.626921] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 342.626938] usb 2-1: Product: SABRENT
[ 342.626953] usb 2-1: Manufacturer: SABRENT
[ 342.626968] usb 2-1: SerialNumber: DB9876543214E
[ 342.639515] scsi host0: uas
[ 342.640972] scsi 0:0:0:0: Direct-Access SABRENT 0204 PQ : 0 ANSI: 6
[ 345.935277] sd 0:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/93 2 GiB)
[ 345.935286] sd 0:0:0:0: [sda] 4096-byte physical blocks
[ 345.935531] sd 0:0:0:0: [sda] Write Protect is off
[ 345.935538] sd 0:0:0:0: [sda] Mode Sense: 53 00 00 08
[ 345.936048] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, does n’t support DPO or FUA
[ 345.936856] sd 0:0:0:0: [sda] Optimal transfer size 33553920 bytes not a mult iple of physical block size (4096 bytes)
[ 345.940078] sda: sda1
* As can be seen this is a USB3.0 SATA 3 adapter from Sabrent. Running in `uas` mode.
* To verify how poorly this was running I tested the speed using:

hdparm -t /dev/sda1
Timing buffered disk reads: 516 MB in 33.25 seconds = 15.52 MB/sec
* Which of course is extremely slow. I then checked the log again using `dmesg`:

[ 1247.365069] usb 2-1: reset SuperSpeed Gen 1 USB device number 3 using xhci_hcd
[ 1247.387663] scsi host0: uas_eh_device_reset_handler success
[ 1279.648929] sd 0:0:0:0: [sda] tag#3 uas_eh_abort_handler 0 uas-tag 4 inflight: CMD IN
[ 1279.648937] sd 0:0:0:0: [sda] tag#3 CDB: opcode=0x28 28 00 03 fa 64 50 00 01 00 00
[ 1279.649085] sd 0:0:0:0: [sda] tag#1 uas_eh_abort_handler 0 uas-tag 2 inflight: CMD IN
[ 1279.649091] sd 0:0:0:0: [sda] tag#1 CDB: opcode=0x28 28 00 00 00 10 00 00 04 00 00
[ 1279.649553] sd 0:0:0:0: [sda] tag#0 uas_eh_abort_handler 0 uas-tag 1 inflight: CMD IN
[ 1279.649559] sd 0:0:0:0: [sda] tag#0 CDB: opcode=0x28 28 00 00 00 0c 00 00 04 00 00
[ 1286.049165] sd 0:0:0:0: tag#4 uas_eh_abort_handler 0 uas-tag 5 inflight: CMD
[ 1286.049173] sd 0:0:0:0: tag#4 CDB: opcode=0x0 00 00 00 00 00 00
[ 1286.065838] scsi host0: uas_eh_device_reset_handler start
* Same issues as discussed in this post.
* Fixing this on libreelec was a bit different though, hence why I wrote this post.
* Navigate to root after logging in, ensure you can edit the `/flash/cmdline.txt` by remounting, then edit file.

cd ..
mount -o remount,rw /flash
nano /flash/cmdline.txt
* I simply adding the below to the beginning of the file and saved:

* And then rebooted:

* After rebooting I checked that the quirk was applied:

dmesg | grep usb-storage
[ 0.673330] usbcore: registered new interface driver usb-storage
[ 1.024033] usb 2-1: UAS is blacklisted for this device, using usb-storage in stead
[ 1.024147] usb 2-1: UAS is blacklisted for this device, using usb-storage in stead
[ 1.024163] usb-storage 2-1:1.0: USB Mass Storage device detected
[ 1.024576] usb-storage 2-1:1.0: Quirks match for vid 152d pid 1561: 800000
[ 1.024726] scsi host0: usb-storage 2-1:1.0
* Which it was, and I then retested the performance:

LibreELEC:~ # hdparm -t /dev/sda1

Timing buffered disk reads: 930 MB in 3.00 seconds = 309.71 MB/sec
* A 20x improvement and it runs so much better. So thank you for this sticky. 🙂

Mouse double click speed

Trouble like me with Mouse double click speed?

Google “lxde double click speed”, there is a hidden file named “.gtkrc-2.0” in your home directory. So if it does not exist, create it. If it does exit, read it before you proceed — it may advise you to use “.gtkrc-2.0.mine” instead.
Type these commands from the prompt, or inside LXTerminal.


rpi_hal from is an incredible rich and uptodate unit for Freepascal to use the I/O of the Raspberry.

From Freepascal programs all works as expected when run as root. Otherwise accessing /dev/mem is causing real problems.

The unit can be used from Lazarus also (avoid the test procedures with writeln’ 😉 ) but also require root access and setting cthreads in the program heading.

For X apps  running as root is not possible with just sudo.
Seems I found a solution here:

I applied method 2:

sudo nano /etc/profile

and added this line as last line

export XAUTHORITY=/home/pi/.Xauthority

Now i can do

$ sudo ./testinit (my simple test program with only the init line of rpi_hal)

and this worked without error, init succeeded.

If you want debugging the app in Lazarus, start Lazarus as root (and ignore all the warnings)

xhost +localhost
sudo /usr/bin/startlazarus

Original text from

Method 2: Globally in /etc/profile
Add the following line to /etc/profile:

export XAUTHORITY=/home/username/.Xauthority
This will permanently allow root to connect to a non-root user’s X server.

Or, merely specify a particular app:

XAUTHORITY=/home/username/.Xauthority appname
where appname is the name of the particular app. (e.g. kwrite

Arduino on Raspberry

Install Arduino on Buster

  1. Arduino 1.8.12 (or higher) from – Software – Arduino ARM 32 bits
  2. Download to e.g. Downloads
  3. cd /Downloads
  4. tar -x -f arduino-1.8.5-linuxarm.tar.xz
  5. cd arduino-1.8.12
  6. sudo ./
  7. and Arduino appears in Home – Programming desktop

Autostart program like minicom at console at boot

Install minicom

sudo apt-get install minicom

setup your system to auto ;login into a commandline session
[use sudo raspi-config]

then at the end of .bashrc put in

if [ $(tty) == /dev/tty1 ]; then
   minicom -s  ##change this to be the thing you want or even a script [full path to]

then reboot your rpi