My HP ProLiant ML310e G8 server uses legacy BIOS rather than UEFI. It runs Gentoo with ZFS RAID-Z1, and the system boots from a 3.7 GB SD card. The disk uses GPT with a small BIOS Boot Partition (EF02) followed by a FAT32 /boot partition, and Limine is installed in BIOS mode.
The system used to boot normally, but the bootloader no longer appears. The firmware skips the SD card and continues with other options such as USB and PXE. The card still accepts writes and has not become read-only.
I rebuilt Limine, the kernel, and ZFS, copied limine-bios.sys into /boot, and reran the BIOS installation against the SD-card device. The SD card appears as /dev/sdf, with /dev/sdf1 as the small partition and /dev/sdf2 mounted at /boot. Is there a BIOS equivalent to efibootmgr for viewing or managing boot entries, and what should I check to determine why the machine no longer boots from this disk?
3 Answers
The device names in the output show the SD card as /dev/sdf, but device names can change depending on what is connected. Before reinstalling, identify the card by its size and model with tools such as lsblk -f or blkid, then install Limine to that whole device. Also inspect the partition table with fdisk or gdisk and confirm the small partition is actually marked as a BIOS boot partition, not merely an arbitrary 1 MiB partition.
For GPT booting in BIOS mode, the small EF02 partition is used by the bootloader, while the FAT32 partition contains /boot. Recheck the partition table and the first sectors of the card, and make sure the BIOS-mode Limine installation completed successfully. A useful comparison is whether the card's partition layout and boot sectors still match a known-good backup. The mounted filesystem alone does not prove that the firmware can find valid BIOS boot code.
Legacy BIOS does not have boot entries in the same sense as UEFI, so there is no direct equivalent to efibootmgr. The firmware normally chooses a disk according to its configured hard-drive boot order, then executes the boot code in that disk's protective MBR. Check the server's boot order and confirm that the SD card is still selected as the first hard disk. Also verify that the installer targeted the whole device, /dev/sdf, rather than /dev/sdf2.
The FAT32 partition is not what creates a BIOS boot entry. BIOS firmware will not maintain a list of Limine entries; it simply tries the selected disk's boot sector. If the firmware no longer lists the SD card at all, check the card reader, boot support settings, and whether the firmware can reliably boot from that type of removable media.