If fai stop with an error, you can go to a second tty via "Alt-F2" and type there any command you like to test.
Exactly, that's what I had in mind.Bonus: You can of course directly edit the disk config file and retry (and even actually attempt to write your configuration to disk) multiple times until it works. So, when you start with a known-working configuration (like the example) and gradually change it to your desired configuration you should find the problematic setting.
Best Maximilian
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