I assume you have the installation stick around still … so could you try:
- Connect the USB installation stick to the computer
- Select the Installation stick as the boot medium
- When you see the “Install Qubes OS R…”/“Test media and …”/“Troubleshooting - …” menu, hit c to get a
grub>
prompt - Type
configfile (hd0,gpt1)/EFI/qubes/grub
and hit theTab
key on your keyboard – did it complete the line to:grub.cfg
?
– if so, hitenter
… if no, try with:configfile (hd1,gpt1)/EFI/qubes/grub
and hitTab
and report/share the result?