I have a Dell T30 server that I am using to run Open Media Vault. To preserve the SATA connections, I decided to install the OS on a USB. I am also using 2 external HDD for data storage.
The BIOS on the server does not let me select which USB to boot from. When all 3 are connected, it picks the device to boot from in random order. I spoke to Dell support and according to them, as long as the other drives don't have any boot files, the BIOS will not select them. I checked this theory by trying to boot with just a EXT4 formatted USB drive and the boot USB drive. After multiple boots, it always picked the boot USB drive. The test USB drive didn't have any files on it.
So I am struggling to figure out what in the data drive is it that the BIOS thinks is a boot file and gets confused. Any tips on how I can troubleshoot this would be highly appreciated.