systemd-boot partition not recognised as bootable

Installing Arch to an old ASUS G74Sx with a Samsung SSD as the main system drive and a Seagate for data I've partitioned and installed system to /dev/sda for systemd-boot as so: root@archiso ~ # parted -l GNU Parted 3.6 Using /dev/sda ... Model: ATA Samsung SSD 860 (scsi) Disk /dev/sda: 500GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 538MB 537MB fat32 boot, esp 2 538MB 500GB 500GB ext4 .... root@archiso ~ # fdisk -l /dev/sda Model: ATA Samsung SSD 860 (scsi) Disk /dev/sda: 500GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 538MB 537MB fat32 boot, esp 2 538MB 500GB 500GB ext4 Configures systemd-boot as so: # blkid ... /dev/sda2: UUID="4b3bca9b-c49f-4414-abd4-96b02c66cd8c" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="d46a8ce3-6a36-4e22-8713-5f8a23c4c471" /dev/sda1: UUID="F948-C4C3" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="6879733a-9c2c-4a9a-8093-875e2c25a111" ... AFTER arch-chroot /mnt root@archiso loader]# cat loader.conf #timeout 3 #console-mode keep default arch timeout 4 console-mode max editor no [root@archiso loader]# cat entries/arch.conf Arch Linux linux /vmlinuz-linux initrd /intel-ucode.img initrd /initramfs-linux.img options root=PARTUUID="d46a8ce3-6a36-4e22-8713-5f8a23c4c471" rw But startup prompts for a boot disk. Please, where is the error? For @telcoM root@archiso ~ # efibootmgr -v EFI variables are not supported on this system. error trace: EFI is enabled in BIOS Running the installer and issuing that command gives a different result root@archiso ~ # efibootmgr -v ** Warning ** : Boot000a is not UEFI Spec compliant (lowercase hex in name) ** Warning ** : please recreate these using efibootmgr to remove this warning. error trace: BootCurrent: 000A Timeout: 0 seconds BootOrder: 000A,0001,0002,0000 Boot0000* Hard Drive BBS(HD,,0x0) dp: 05 01 09 00 02 00 00 00 00 / 7f ff 04 00 Boot0001* CD/DVD Drive BBS(CDROM,,0x0) dp: 05 01 09 00 03 00 00 00 00 / 7f ff 04 00 Boot0002* asmt test HD(1,MBR,0x5cfcc5eb,0x185000,0x7800)/File() dp: 04 01 2a 00 01 00 00 00 00 50 18 00 00 00 00 00 00 78 00 00 00 00 00 00 eb c5 fc 5c 00 00 00 00 00 00 00 00 00 00 00 00 01 01 / 04 04 06 00 00 00 / 7f ff 04 00 Boot000a* UEFI: USB USB Hard Drive PciRoot(0x0)/Pci(0x1d,0x0)/USB(1,0)/USB(3,0)/HD(1,MBR,0x5cfcc5eb,0x185000,0x7800) dp: 02 01 0c 00 d0 41 03 0a 00 00 00 00 / 01 01 06 00 00 1d / 03 05 06 00 01 00 / 03 05 06 00 03 00 / 04 01 2a 00 01 00 00 00 00 50 18 00 00 00 00 00 00 78 00 00 00 00 00 00 eb c5 fc 5c 00 00 00 00 00 00 00 00 00 00 00 00 01 01 / 7f ff 04 00