crunchynuts

Following this one up incase it helps someone in the future.
- nothing useful from memtest/syslog/diagnostics
- did all the recommended 6.12.x tweaks.
- Removed all but 1 stick of RAM, seems to last longer but still crashes after about a week.
 
Noticed that when it did crash I could still SSH in and access the CLI, although it did not register and commands.
- I believe that when there were writes or reads to the flash under circumstances (unsure when unraid does this specifically). It would cause various system components to halt/and not respond (UI/docker/etc).. CLI was strangely accessible.
- Hard pressing the power button initiated a hard shutdown, and I noticed that Docker would take a long time to respond to a stop (docker is stored on flash)
- After a while the flash would stop detecting in the BIOS POST as a bootable drive.
- plugged into a windows machine and it was fine however this pointed to issues with the flash USB.
 
Decided to buy a brand new USB flash and reinstall latest 6.12.6 copied over the config folder.
- Chose not to restore backup incase there were other corrupt files
 
Reinstalled all RAM sticks and system is somewhat stable now for 3 days, use to crash daily.
If it makes it past 10 days then will consider it stable.
 
TLDR, check your flash if its more than a few years old, it's cheaper than checking other hardware components.