I wonder if there is a possibility to freeze /var/log/dmesg file of an USB-stick installed system where boot has not started Xserver, no access to an output device (printer), and only gets to a fully functional (bash commands and the file system accessable) console/terminal on the screen? If this file would be available on another (working) computer, I think this could help in case of error detection.
Would not 'knoppix 2' give you a startup to a terminal?
Or perhaps, 'init 1' to stop unnecessary services.
Interesting approach...I'll try...keep you posted..