knute
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Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 2:44 am

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!

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rpdom
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Re: Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 4:36 am

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?)
Unreadable squiggle

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DougieLawson
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Re: Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 11:07 am

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.
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knute
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Re: Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 5:59 pm

rpdom wrote:
Sat Aug 15, 2020 4:36 am
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
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Joined: Thu Oct 23, 2014 12:14 am
Location: Texas
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Re: Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 6:01 pm

DougieLawson wrote:
Sat Aug 15, 2020 11:07 am
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!

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DougieLawson
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Re: Kernel won't roll back with rpi-update?

Sat Aug 15, 2020 6:52 pm

knute wrote:
Sat Aug 15, 2020 6:01 pm
DougieLawson wrote:
Sat Aug 15, 2020 11:07 am
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.
Any language using left-hand whitespace for syntax is ridiculous

Any DMs sent on Twitter will be answered next month.
Fake doctors - are all on my foes list.

Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

knute
Posts: 664
Joined: Thu Oct 23, 2014 12:14 am
Location: Texas
Contact: Website

Re: Kernel won't roll back with rpi-update?

Thu Aug 20, 2020 9:12 pm

Thanks Dougie, I'll give those a try.

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