Were you using GPT partition table in pfSense ? If so, then it needs to be thoroughly erased, before the MBR partition table in IPFire would be reliable. In Linux, the “gdisk” tool (also sometimes called gptfdisk) can do that via the -z option.
IPfire erase the fist 10MB of a disk so change from gpt to mbr should not a problem.
Would a discard operation be required after the erasure and prior to creating an MBR partition table ?
Niormal it is not needed at all. But mkfs.ext4 try it if it detect an ssd. Im not really sure what’s the reason for the problem. Maybee it is also a bios problem that select a wrong CHS/LBA translation. Can you check the bios settings if there is a wrong translation mode (e.g. Large instead of LBA) active?
You could try unplug all drives.
Plug in blank USB drive/stick.
Plug in ipfire USB stick with iso.
And install to blank USB.
This will help narrow your problem.
To drive or other hardware failures.