I am working on a RPI 3. Operating system is Archarm.
I tried a suggestion to add
arm_control=0x200 in /boot/config.txt for my RPI 3.
So, it was expected to run in Armv8 mode.
However, after rebooting RPI, the system stuck almost immediately in the "Rainbowscreen".
You can imagine that I was not able to access /boot/config.txt to strip out the ARMv8 mode line.
To fix the problem I tried to mount the sd card in my computer. However there is no config.txt on the first partition!
Any ideas to access /boot/config.txt apart from a complete renstall of the operating system?