Using ROCKNIX Guide

Disable GRUB Menu at Boot

You can disable the GRUB device select screen that appears at boot. This will shave seconds off your boot-time. The recovery option listed has been tested and it doesn't appear to do anything useful when you actually need a recovery.

1. Connect to the rig:
   ssh root@SM8250.local
2. Remount the boot partition read-write:
   mount -o remount,rw /flash
3. Back it up first so it's reversible:
   cp /flash/EFI/BOOT/grub.cfg /flash/EFI/BOOT/grub.cfg.bak
4. Set the menu timeout to 0 — skips the GRUB device-picker wait (edit the EFI config, not /flash/boot):
   sed -i 's/set timeout=2/set timeout=0/' /flash/EFI/BOOT/grub.cfg && sed -i 's/set timeout=-1/set timeout=0/' /flash/EFI/BOOT/grub.cfg
5. Verify both timeouts now read 0 (if either still shows 2 or -1, the remount in step 2 didn't take — redo from step 2):
   grep timeout= /flash/EFI/BOOT/grub.cfg
6. Flush and put it back read-only:
   sync && mount -o remount,ro /flash