these are not high end boards
and they are old or NOS
my under $20 N4F used a different and older one and it worked very well
if you boot from USB on older hardware it likely must be a FAT formatted flash
this is easier than seeking a bios upgrade that might recognize GPT boot
I suggest wipe everything from the flash
format the whole flash as a FAT file
re install N4F
lots of USB flash get around compatibility problems in unique ways
usually this works, but often enough it does not
booting starts in real mode and as such is totally dependent on hardware compatibility
my N4F with a dis-similar Intell board booted from a hard drive on the board ATA-100 PATA line
the storage drives used a card in the expansion slot. [did not have SATA]
by booting from a Hdd as the boards were designed,
thus I avoided any USB problems.
viewtopic.php?f=63&t=78424 thread 3300 Mhz Intel i3, 1 TB ZFS mirror, available RAM 7.823 Gb, 64 bit NAS4Free 9.1.0.1 rev 573 [88 watts, 48 Mbps]
2 thread 1600 Mhz atom/ion, 1 TB ZFS mirror, available RAM 3.083 Gb, 64 bit NAS4Free-9.1.0.1 rev 573 [27 watts, 35 Mbps]
2 thread 3900 Mhz AMD A6-6400K, 2 TB ZFS Mirror, available RAM 7.557 Gb, 64 bit Nas4Free 9.3.0.2.1771 [89 watts, 68 Mbps]
Works perfect!