So some time back I replaced the OS on my two QNAP NAS devices and replaced with TrueNAS but at "random" times the boot-pool suspends or it decides to not boot. Doesn't mater what USB port, what USB device, if I use M.2 to USB, etc.
Today I decided to use clover as a bootloader to boot TrueNAS from one of the two NVME SSD I have on a PCIe card and it works great.
I tried enabling EFI using the bios to for the insyde BIOS but that just enables EFI, there is no oprom for NVME in this BIOS and I'm not going to risk modifying the BIOS for it.

The instructions on the internet are terrible so here is an easy guide:

Clover: https://github.com/CloverHackyColor/CloverBoo … loader/releases
Rufus: https://rufus.ie/en/

1. Install TrueNAS or whichever OS
2. Use rufus to make a USB drive bootable using clover
3. Boot clover on device
4. Put USB drive in another computer
5. Check \EFI\CLOVER\misc\preboot.log on USB
6. Look for first entry for HD (If this entry isn't correct then the timeout will not work although the system will boot, very confusing)
Example: PciRoot(0x0)\Pci(0x1,0x0)\Pci(0x0,0x0)\Pci(0x1,0x0)\Pci(0x0,0x0)\NVMe(0x1,66-08-00-7F-5C-A7-79-64)\HD(2,GPT,D5B1C2AA-9F8E-4218-BFFA-6D8731F4DA58,0x1800,0x100000)

7. Make a note of the entry.
8. Open \EFI\CLOVER\misc\config.plist

9. Add GUID from #5 entry to config.plist under <key>Boot</key> section in <string> </string>
Example: <string>D5B1C2AA-9F8E-4218-BFFA-6D8731F4DA58</string>

10. Add "timeout" and "5" above <key>DefaultVolume</key> to timeout to 5 seconds or 0 to go straight to boot. -1 to boot to the menu.
Example:
<key>Timeout</key>
<integer>5</integer>

11. Copy the following drivers from \EFI\CLOVER\drivers\OFF and place them into \EFI\CLOVER\DRIVERS\UEFI and \EFI\CLOVER\DRIVERS\BIOS

*It's likely that not all of these are needed but I'm too lazy to check.
ApfsDriverLoader.efi
AptioInputFix.efi
AudioDxe.efi
FSInject.efi
Fat.efi
OpenRuntime.efi
SMCHelper.efi
VBoxHfs.efi
UsbMouseDxe.efi
CsmVideoDxe.efi
EmuVariableUefi.efi
NvmExpressDxe.efi
PartitionDxe.efi
UsbKbDxe.efi

12. Place USB in the system and change the BIOS settings to boot from it.