Hello,
I'm having trouble getting my E7470 to detect/run my Catalina installer USB. I have updated bios to latest 1.22.8, I have secure boot off, legacy disabled, etc. I made the USB using my iMac and using the terminal command in the guide, then installed the latest Clover on the drive and put the correct bootpack files in EFI/Clover and all that jazz, and every time I try to boot it(pressing f12 at the dell power on screen) it never shows up in the list of bootable drives. I've tried updating every kext I possibly could, I've tried various bios options(disabling/enabling TPM and small tweaks like that before starting all over again and again), and I've tried 3 different USB drives from 3 different brands in all 3 of the USB ports on this machine. It's frustrating because I cannot for the life of me figure out how to get this machine to boot a USB stick in UEFI mode, let alone detect it. Looking at the drive (even with hidden files shown using Cmd+Shift+.) and everything appears to be there and in order. I haven't found anyone on here with this issue using the search function(most people actually make it to the part where the installer starts before running into problems) but I did find this article: https://www.dell.com/support/article/us/en/04/sln302982/usb-boot-device-missing-from-the-f12-boot-menu-on-the-latitude-e7470?lang=en
The problem with that is that the only solution they list is to update the bios, which I've done. Maybe I'm missing a key step in making the USB bootable, but I've followed the guide carefully and multiple times, so I'm starting to wonder if it really is just a problem with my machine.