Thank you for your help. I'm uncomfortably aware that my problem does not belong here. Feel free to move me elsewhere. Here is some more detail on my experience anyway : yes, wdt, I can indeed boot from an SD card, but not from the emmc. The mrfixit Debian is the only os I've successfully booted. The old 20.04 Manjaro is still stuck on the emmc and I would love to replace it with Debian for now. When it boots up, the Debian on the SD card fails to run a software upgrade : the upgrade application hung for more than 30 minutes and i haven't tried it since. The computer does not power off properly : I select 'shut down' and get stuck with a black screen and a green LED light. The SD card shows up as MNJRO in file manager. Presumably this is short for Manjaro. Therefore I presume my attempt to write a Debian image to the SD card that would prompt to install onto the emmc is incomplete . The help I got with DD commands is much appreciated. It's basic stuff for others, but I'm grateful someone took the time to walk me by the hand through it. With my new understanding of how this works, I had a go at following the instructions to create a proper bootable SD card of Debian. This is where I got:
dd: failed to open 'dev/mmblk2': No such file or directory
I had used the same SD card.
Question: what's the right file path for the SD card? The computer is just called ciaran@ciaran
dd: failed to open 'dev/mmblk2': No such file or directory
I had used the same SD card.
Question: what's the right file path for the SD card? The computer is just called ciaran@ciaran