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Downloading precompiled coreboot image…–2023-08-07 21:23:28-- https://source.puri.sm/coreboot/releases/raw/f3a6cee73c177e0bfda30a04b9af01af782bf1c2/librem_13v2/coreboot-librem_13v2-4.20.1-Purism-1.rom.gz
Resolving source.puri.sm (source.puri.sm)… 143.198.145.103
Connecting to source.puri.sm (source.puri.sm)|143.198.145.103|:443… connected.
ERROR: The certificate of ‘source.puri.sm’ is not trusted.
ERROR: The certificate of ‘source.puri.sm’ has expired.
Can mean that the date/time on your computer is wrong. That would be the first thing that I would check.
That IP address appears to be correct. The certificate (itself and any certificate in the CA chain) does not appear to have expired. My browser appears to be happy with it (and I am a frequent visitor to that site, making minor edits to documentation).
It is my assumption that you obtained this error in the last hour or so.
Thankyou for your help.
The answer is: I was using an old PureOS. I downloaded and made a bootable USB with Byzantium and installed on my OS. Made sure the system clock was updated. Then entered the flash firmware commands. Everything worked.