The manual Linux instruction are https://docs.unraid.net/unraid-os/getting-started/manual-install-method/, but the install script is finiky and there isn't enough detail to navigate this mine-fields.
- Create new MBR partiiton table
- Add one
W95 FAT32 (LBA)FAT32 partition
$ sudo mount /dev/sda1 /mnt
$ sudo unzip unRAIDServer-6.12.14-x86_64.zip -d /mnt/$ /mnt/make_bootable_linux
INFO: make_bootable_linux v1.3
INFO: The following device appears to be the unRAID USB Flash drive: /dev/sda
Permit UEFI boot mode [Y/N]: y
INFO: unRAID USB Flash drive currently mounted to /mnt, copying temporary installer files to /tmp/UNRAID
umount: /mnt: must be superuser to unmount.
To continue you may need to enter your admin password
INFO: Unmounting /dev/sda
umount: /dev/sda: not mounted.
INFO: Installing Syslinux bootloader on /dev/sda1
Hidden (2048) does not match sectors (63)
Hidden (2048) does not match sectors (63)
Hidden (2048) does not match sectors (63)
Hidden (2048) does not match sectors (63)
INFO: Writing MBR on /dev/sda
0+1 records in
0+1 records out
447 bytes copied, 3.6799e-05 s, 12.1 MB/s
INFO: the Unraid OS USB Flash drive is now bootable and may be ejected.$ sudo fdisk -l /dev/sda
Disk /dev/sda: 115.1 GiB, 123589361664 bytes, 241385472 sectors
Disk model: 3.2 Gen 1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0x00000000
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 241385471 241383424 115.1G c W95 FAT32 (LBA)