LCD35

[pmcgilla]

So, I bought one of these cute little LCD panels that plugs into and RPi and after a couple of tries got it to work just fine. Even figured out how to rotate screen 180 so it can sit upright on a shelf.

Then I (maybe) broke it, by doing apt-get update and apt-get upgrade. Now I have a white screen and no writing. Before reloading from scratch, which may not fix it, where else can I look? Tried rerunning the startup program to no avail. If I reload from scratch, easy enough, but then do an upgrade, will it break again?

Patrick

[echmain]

So, I bought one of these cute little LCD panels that plugs into and RPi and after a couple of tries got it to work just fine. Even figured out how to rotate screen 180 so it can sit upright on a shelf.

Then I (maybe) broke it, by doing apt-get update and apt-get upgrade. Now I have a white screen and no writing. Before reloading from scratch, which may not fix it, where else can I look? Tried rerunning the startup program to no avail. If I reload from scratch, easy enough, but then do an upgrade, will it break again?

Patrick

You didn’t mention what display you have but I had the exact problem a few days ago. Bottom line, I had to update the Python libraries.

viewtopic.php?f=28&t=281131

[pmcgilla]

Well, actually I did it was the 3.5 inch touchscreen that plugs straight into the pi. I just tried running update and upgrade, but it found nothing to do. The latest Raspian Buster is loaded. What or how did you update python libraries?

[pmcgilla]

Speaking of Python, I have several version loaded and the oldest acts like the default, How do you make Python 3.7 the default?

[echmain]

Well, actually I did it was the 3.5 inch touchscreen that plugs straight into the pi. I just tried running update and upgrade, but it found nothing to do. The latest Raspian Buster is loaded. What or how did you update python libraries?

That's fine, but in my case it wasn't apt update/upgrade that fixed it.

I needed to do pip3 install --upgrade adafruit_blinka

apt update/upgrade won't upgrade these individual libraries because they weren't installed with apt.

If your screen uses Python libraries you might need to do the same/similar.

[knute]

I've got two brands of those little screens that don't work with the 5.4 kernel. One is a Waveshare and the other is an goodtft/LCDwiki(?). The only fix I found was to go back to the 4.19 kernel. I managed to do that with rpi-update on one but the other I had to burn a new card with the 05/27 Raspbian to get it to work. Just don't upgrade it.

I would assume that all the makers of those little screens with come out with new drivers soon but I haven't seen any yet.

Here is the command I used to get the one to revert to the 4.19 kernel:

sudo rpi-update e1050e94821a70b2e4c72b318d6c6c968552e9a2

[pmcgilla]

Yes, that works for me.

[W. H. Heydt]

I've got two brands of those little screens that don't work with the 5.4 kernel. One is a Waveshare and the other is an goodtft/LCDwiki(?). The only fix I found was to go back to the 4.19 kernel. I managed to do that with rpi-update on one but the other I had to burn a new card with the 05/27 Raspbian to get it to work. Just don't upgrade it.

I would assume that all the makers of those little screens with come out with new drivers soon but I haven't seen any yet.

Here is the command I used to get the one to revert to the 4.19 kernel:

sudo rpi-update e1050e94821a70b2e4c72b318d6c6c968552e9a2

This https://github.com/notro/fbtft/wiki#ste ... sing-fbtft web page may have a clue to the underlying problem. 5.4 is missing modules that the SPI-connected screens rely on. Not sure what the solution is going to be, but for now, yes, don't upgrade. However, that is a very bad solution in the long run as it means one doesn't get security updates.

[knute]

I managed to get my other one working by installing new 5/27 RPiOS, rebooting, running the rpi-update rollback command, and rebooting again. Not sure why I couldn't get it to work before.

[W. H. Heydt]

For the TinyLCD 35 it looks like it may need a new dtbo module for kernel 5.4. Maybe...

[cyber7]

I also had the same problem with OctoPI and doing an update. Had to go back, as it seems the update messed up the display...

[cyber7]

Just a quick update:
It seems this has been fixed. I have successfully installed PEPPY and the latest Rasberry OS with the drivers... I will report on my latest octopi buster release once installed... (Do not want to run an update on my current OctoPi system as it is printing 24/7! - getting ready for XMAS)