Kernel won't roll back with rpi-update?

[knute]

I have one of those small 3.5 inch video screens on one of my Pi4s and it stopped working with the 5.4.0 kernel. I used this command to roll back the kernel to 4.19.118:

sudo rpi-update e1050e94821a70b2e4c72b318d6c6c968552e9a2

and it worked fine. But now when I run that command rpi-update says:

pi@hamclock:~ $ bin/kernel-4.19
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** Performing self-update
*** Relaunching after update
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** Your firmware is already up to date

and the kernel is still 5.4.0.

Is it not possible to roll the kernel back from here?

I don't want to have to reload the OS again like I did with my other one of these. Either the screen manufacturers will come out with new drivers or they won't but in the meantime I would like to still use my Pi for its intended purpose.

Thanks!

[rpdom]

Try this before running the rpi-update again:

Code: Select all

sudo rm /boot/.firmware_revision

That file holds the "currently installed" firmware/kernel version, but doesn't get cleared when apt installs a new kernel or firmware.
(Perhaps RPT could consider making the raspberrypi-kernel and raspberrypi-bootloader packages delete that file if it exists as part of the post-inst script?)

[DougieLawson]

My advice is go forwards. There was another update to the 5.4.51 kernel/bootcode/rpi-eeprom packages with apt yesterday. That includes all of the fixes for the known bugs in 5.4.51.

[knute]

Try this before running the rpi-update again:

Code: Select all

sudo rm /boot/.firmware_revision

That file holds the "currently installed" firmware/kernel version, but doesn't get cleared when apt installs a new kernel or firmware.
(Perhaps RPT could consider making the raspberrypi-kernel and raspberrypi-bootloader packages delete that file if it exists as part of the post-inst script?)

Thanks very much, that worked!

[knute]

My advice is go forwards. There was another update to the 5.4.51 kernel/bootcode/rpi-eeprom packages with apt yesterday. That includes all of the fixes for the known bugs in 5.4.51.

From what I've read the issue with these little screens is not going to be resolved by fixes to RPiOS but by new drivers from the manufacturers. So until that happens, if it ever does, this is an easy fix to get it working again.

Thanks!

[DougieLawson]

My advice is go forwards. There was another update to the 5.4.51 kernel/bootcode/rpi-eeprom packages with apt yesterday. That includes all of the fixes for the known bugs in 5.4.51.

From what I've read the issue with these little screens is not going to be resolved by fixes to RPiOS but by new drivers from the manufacturers. So until that happens, if it ever does, this is an easy fix to get it working again.

Thanks!

It's not a new driver, it's a device tree overlay. There's plenty of the random ebay screens that are already supported.
https://github.com/swkim01/waveshare-dtoverlays
https://github.com/goodtft/LCD-show

Or write your own overlay, it's not hard to steal the dts source code for one that's close enough and hack it.

[knute]

Thanks Dougie, I'll give those a try.