[Arm-dev] rainbow screen after "yum update" on 5/18/2018

Sat May 19 20:44:56 UTC 2018
Pablo Sebastián Greco <pablo at fliagreco.com.ar>

Hi Kenneth

El 19/5/18 a las 14:18, Kenneth Freidank escribió:
> I just updated my Centos7 Pi3 "yum update" on 5/18/2018, and now I am 
> facing a rainbow screen.  Red pwr light is nice and strong, even 
> changed power supplies.  Green ACK light blinks 2 times and stays 
> off.  Screen is stuck on the rainbow - no activity, nothing, with or 
> without the USB drive, nothing.  USB drive does not power up either - 
> nothing.  Tried pressing the keys 1 to 4 at power up, then any key on 
> multiple pwr ups, no effect.  Found a similar post on 
> https://www.raspberrypi.org/forums, search "raspberry pi3 stuck on 
> rainbow screen after Jessie update".
>
> Removed micro card and read files on another machine
>
> Without listing all the files individually, kernel7.img, the dtb files 
> bcm2708-rpi-xxx.dtb, bcm2710-rpi-xxx.dtb, bcm2835-rpi-xxx.dtb, 
> bcm2836-rpi-xxx.dtb, gcm2837-rpi-xxx.dtb.  All are dated 5/18/2018, 
> the day of my yum update.
>
> The kernel is kernel-4.14.27-v7.1.e7.img dated 3/19/2018.
>
> Other files bookcode.bin, fixup*.*, LICENCE.broadcom, start*.elf, 
> COPYING.linux all date 3/16/2018.
>
> A file initrd-plymouth.img dates 2/26/2018.
>
> I also see what look like older kernel files: 
>  kernel-4.9.75-v7.1.el7.img - 1/9/2018; kernel-4.9.70-v7.1.el7.img - 
> 12/19/2017; kernel-4.9.64-v7.1.el7.img - 11/24/2017; 
> kernel-4.4.26-v7.1.el7.img - 10/22/2016.
Looking at that amount of older kernels makes me suspect that you run 
out of space in /boot while updating, please check that .
>
> Any ideas on how to downgrade to previous kernel or how to fix this?  
> Can't get into single user mode - pressing keys on pwr up has no 
> effect.  I don't know enough about the kernel and the boot process to 
> start messing with them.  I am stuck.

Copying some of the older files in /boot should make the older kernel 
work, but please don't do that until we checked for disk space.
Thanks.
Pablo