Using APU2 - initially used Core 12 and even though it booted from the USB stick, it did not detect the USB stick.
Reverted to pcengines ancient 6.4 version which worked.
Just tried Core 11.1 and it works.
usb 3-2: new SuperSpeed Gen 1 USB device number 2 using xhci_hcd
usb-storage 3-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 3-2:1.0
scsi 2:0:0:0: Direct-Access PNY USB 3.1 FD PMAP PQ: 0 ANSI: 6
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 60628992 512-byte logical blocks: (31.0 GB/28.9 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 23 00 00 00
sd 2:0:0:0: [sdb] No Caching mode page found
sd 2:0:0:0: [sdb] Assuming drive cache: write through
sdb: sdb1 sdb2
sd 2:0:0:0: [sdb] Attached SCSI removable disk