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I've flashed StickyFingers-Kali-Pi-armhf-180607 to my Raspberry Pi 3 B+ with Waveshare 3.5" LCD (B). I update and configure the unit for my specific screen using the guide's instructions, entering the following commands:

sudo apt update
sudo apt upgrade
cd /usr/local/src/re4son-kernel_4.9.80-20180410
mount /dev/mmcblk0p1 /boot
./re4son-pi-tft-setup -u
./re4son-pi-tft-setup -t wave35b -d /home/pi
./re4son-pi-tft-setup -b cli
./re4son-pi-tft-setup -a pi

After this, the screen works, but the refresh rate is very slow. I'm not sure how to measure it, but I would eyeball it at around 0.5Hz-1Hz maybe. I am not sure if this is working as intended or not; this is my first time using this screen.

The Waveshare screen connects to the RPi solely via the GPIO pins; it does not use HDMI. Previously, I had a knock-off screen which did use HDMI, and it had a 60Hz refresh rate. Since the knock-off screen took up the HDMI port, I decided to get the Waveshare screen since it could connect to the Pi without using the HDMI port.

Would this explain why the refresh rate on the Waveshare screen is so low? Or did I perhaps configure something wrong? I did find a video review of the Waveshare screen which had the same result as me, and the author said that the low refresh rate is the result of the limitation of the GPIO pins exporting the "framebuffer" and even small resolutions like this appear to be too much to refresh quickly. He did say he found some tweaks that allowed him to increase the refresh rate considerably (at the cost of bit-depth), but he did not elaborate as to how those tweaks were done. I've seen a few sources reference editing the /boot/config.txt file to say something like:

dtoverlay=waveshare35b:speed=41000000,fps=50

But my /boot/config.txt file is blank. I added the above line to the blank file, but did not notice a change on reboot.

Any insight is appreciated.

  • i think u have to mount it first: mount /dev/mmcblk0p1 /boot – guest Jun 24 '18 at 3:11

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