SSDs from some vendors are not detected on USB 3 port . They boot from USB 2.0 port. you can add a quirk to the cmdline.txt with VendorID and DeviceID to get this corrected. Check below link
SSDs from some vendors are not detected on USB 3 port . They boot from USB 2.0 port. you can add a quirk to the cmdline.txt with VendorID and DeviceID to get this corrected. Check below link