Librem 15v4 and non-free Purism repo for microcode

[wctaylor]

You might run into this issue then:

USB not recognized in BIOS - Librem Mini V2

Looks like this is the Purism firmware utility script, which seems like it’s gotten out of date. It is trying to clone the master branch of the flashrom project, but flashrom has changed their structure - they now use a branch called main instead of one called master (as of July, 2024). You should be able to open the coreboot_util.sh script in a text editor, and replace the word master with the word main in two places: line 866 and line 883. But it might be best to get input from Purism direct…