If you are booting bios in legacy mode from usb try installing clover on the usb with legacy install option, if booting the laptop in UEFI mode install clover in UEFI mode onto usb. maybe thats why it does not show up in your F12 boot menu selection screen.
I compiled latest clover trunk rev 4045 because 4035 has some issues that are corrected in latest trunk in case thats the issue you are having.
Clover_v2.4k_r4045.zip