Disk Layout and Bootloader
Garden Linux on-premises installations (ISO and PXE boot) use a standardized GPT partition layout with firmware-specific bootloader configuration. This page describes the partition scheme and bootloader installation for both Legacy BIOS and UEFI systems.
Partition Layout
The installation creates a GPT partition table with two partitions:
| Partition | Type | Size | Format | Purpose |
|---|---|---|---|---|
| EFI | C12A7328-F81F-11D2-BA4B-00A0C93EC93B (ESP) | 510 MiB | VFAT | Bootloader storage (Legacy: syslinux stages, UEFI: systemd-boot + UKI) |
| ROOT | Architecture-specific (see below) | Remaining space | ext4 | Garden Linux root filesystem |
This layout supports both Legacy BIOS and UEFI firmware using the same partition structure. The EFI System Partition (ESP) is used by both firmware types:
- Legacy BIOS — Stores syslinux bootloader stages (stage 2 and higher)
- UEFI — Stores systemd-boot bootloader and kernel images
Root Partition Type GUIDs
Garden Linux uses architecture-specific root partition GUIDs from the Discoverable Partitions Specification. This enables automatic root partition discovery by systemd without requiring root= kernel parameters or /etc/fstab entries.
| Architecture | Root Partition GUID |
|---|---|
| x86-64 (amd64) | 4f68bce3-e8cd-4db1-96e7-fbcaf984b709 |
| ARM64 (aarch64) | b921b045-1df0-41c3-af44-4c6f280d3fae |
WARNING
The generic Linux filesystem GUID (0FC63DAF-8483-4772-8E79-3D69D8477DE4) should not be used for root partitions as it disables automatic discovery features.
Bootloader Installation
The installation script detects the firmware type and installs the appropriate bootloader automatically.
Legacy BIOS — syslinux
For Legacy BIOS systems, the installer installs syslinux:
- Writes a new Master Boot Record (MBR) to the first sector of the disk
- Installs syslinux stages 2+ to the EFI partition
- Configures syslinux to boot the kernel from the ROOT partition
The syslinux bootloader configuration includes console output to both serial (ttyS0) and VGA (tty0).
UEFI — systemd-boot
For UEFI systems, the installer installs systemd-boot:
- ISO installations — Use Boot Loader Specification (BLS) entries in
/efi/loader/entries/ - PXE installations — Use Unified Kernel Images (UKI) which combine the EFI stub loader, kernel image, initramfs, and kernel command line into a single EFI PE executable
UKI images can be signed for Secure Boot support.
The systemd-boot configuration includes console output to both serial (ttyS0 for ISO, ttyS1 for PXE) and VGA (tty0).
Firmware Migration
The identical disk layout for both firmware types allows migrating an installation between Legacy BIOS and UEFI systems by re-running the appropriate bootloader installation script on the target system.
Related Topics
- Boot Modes — Technical background on BIOS and UEFI boot processes
- Install Using ISO — ISO installation guide
- Install Using PXE Boot — PXE network boot installation guide