This script allows you to easily change the unRAID bootloader from SYSLINUX to GRUB with support BTRFS and XFS USB Boot media with TRIM enabled (please note that BTRFS and XFS are considere experimental).

Please create a backup from your USB Boot Device before continuing in case something goes wrong!

To convert the bootloader from your existing unRAID vfat installation issue these commands from a unRAID terminal (the Array must be stopped before issuing these commands):

wget -O /tmp/bootloader_convert https://git.minenet.at/ich777/unraid-grub/raw/branch/master/bootloader_convert
chmod +x /tmp/bootloader_convert
/tmp/bootloader_convert vfat

After the script finished your server will automatically reboot and you should be greeted by the GRUB bootscreen:

EXPERIMENTAL

To convert your existing vfat USB Boot Device to BTRFS or XFS change the last command to:
/tmp/bootloader_convert btrfs for BTRFS or
/tmp/bootloader_convert xfs for XFS.