I encountered a similar problem with my Intel Desktop. Whereas my other PCs only require me to use the F12 key to choose a USB flash card as the boot device, or to place it first in the boot configuration, the Intel PC chooses to consider flash devices greater than 4GB (or maybe it's 2GB?) as drives. In order to have such devices appear in the boot configuration lineup, you have to rearrange them first in the drive lineup (because only so many places are available, IIRC). This is all a bit fuzzy because it's been a few months since I last dealt with this problem.
SanDisk 2TB Ultra 3D NAND SSD, Internal Solid State Drive - SDSSDH3-2T00-G26
$149.99
SanDisk 2TB Ultra 3D NAND SSD, Internal Solid State Drive - SDSSDH3-2T00-G25
$129.99
Western Digital 250GB WD Blue SA510 SATA SSD, Internal M.2 2280 - WDS250G3B0B
$39.99
Team Group 512GB T-FORCE VULCAN Z 2.5" SATA III 3D NAND Internal SSD
$30.99
Patriot P210 128GB 256GB 512GB 1TB 2TB 2.5" SATA 3 6GB/s Internal SSD PC/MAC Lot
$14.99
Intel DC S3510 Series 120GB SSD 2.5" 6Gb/s SATA Solid State Drive SSDSC2BB120G6K
$9.99
Netac 1TB 2TB 512GB Internal SSD 2.5'' SATA III 6Gb/s Solid State Drive lot
$13.99
Fanxiang SSD 512GB 1TB 2TB 4TB 2.5'' SSD SATA III Internal Solid State Drive lot
$13.99
Fanxiang 256GB 512GB 1TB 2TB 4TB Internal SSD 2.5" SATA III 6GB/s for PC/MAC Lot
$197.99
Fanxiang 4TB 2TB 1TB SSD 550MB/s 2.5'' SATA III Internal Solid State Drive lot
$209.99