ForeB Bootloader Configuration Reference

ForeB uses a GRUB-like configuration file (forebo.cfg) stored on the EFI System Partition at \forebo\forebo.cfg. The parser lives in uefi/core/config.c and populates a POD struct defined in include/forebo_cfg.h.

File Format Basics

• Lines starting with # are comments. Blank lines are ignored.
• Paths are ESP-absolute; both / and \ separators work.
• Quotes around titles/values are stripped by the parser.
• Unknown keys are silently ignored (forward/backward compatibility).
• The parser is tolerant: malformed lines are skipped, never faulted.

# This is a comment
timeout=60
background=/forebo/bg.bmp

Capacity limits: 64 max entries, 8 modules per entry, 64-char titles, 256-char paths, 256-char command lines, 8-level submenu nesting.

Global Settings

The default path resolves case-sensitively level by level; if it lands on a submenu it descends to its first child automatically. On any mismatch the first top-level non-submenu row is used.

Menu Entry Syntax

Each entry is a menuentry "Title" { ... } block. The type= key selects the boot method (defaults to forest).

menuentry "Entry Title" {
    type=<kind>
    kernel=/forebo/kernel.elf
    icon=os
    cmdline=""
}

Per-entry keys: type, icon, background, cmdline, kernel, module (repeatable, up to 8), module2 (alias of module), vmlinuz, initrd, chain.

Boot Methods

Setting vmlinuz= on a forest entry auto-promotes to linux. Setting chain= on a forest entry auto-promotes to chainload.

Forest OS

menuentry "Forest OS" {
    type=forest
    kernel=/forebo/kernel.elf
    module=/forebo/initrd.tar
    icon=os
    cmdline=""
}

Linux (EFI-stub)

menuentry "Linux" {
    type=linux
    vmlinuz=/forebo/vmlinuz
    initrd=/forebo/initrd.img
    cmdline="root=/dev/sda2 ro quiet loglevel=3"
    icon=tux
}

Chainload

menuentry "Chainload GRUB (USB)" {
    type=chainload
    chain=/EFI/BOOT/BOOTX64.EFI
    icon=grub
}

menuentry "Boot removable device" {
    type=chainload
    icon=usb
}

Icon short names (resolved to /forebo/icons/.tga): os, text, safe, gear, shield, reboot, ubuntu, debian, arch, fedora, mint, tux, windows, grub, usb, disk, terminal.

Theme Configuration

Named Presets

theme=forest

Available: forest (default), midnight, nord, dracula, gruvbox, solarized, amber, matrix, rose, ocean, mono. Any color_* key overrides a single color on top of the preset.

Colors (0xRRGGBB, also accepts #RRGGBB)

Cursor and Input

Window Skin

window_skin=flat|beveled|glass (default: beveled).

Custom Images (ESP-absolute TGA/BMP)

Keep panel/window/titlebar/button <= 4096px; cursor <= 64px.

Visual Effects

Off by default (each forces a full-frame flip).

Audio (PC Speaker)

All off by default. Keys: pcspeaker (master on/off), audio_volume (0..100), and per-event pairs audio_{nav,select,open,error,back}_freq / audio_{nav,select,open,error,back}_ms (Hz and ms).

Menu Style Configuration

menu_style picks one of 30 built-in layout presets:

classic minimal terminal flat modern card neon outline underline invert
brackets sidebar-left sidebar-right banner-top dock-bottom fullscreen
centered compact spacious retro glass hacker ribbon framed dashed
spotlight pill boxed ghost elegant

All fields below are optional; omit any to inherit from the preset. -1 means "inherit".

Submenu Syntax

Submenus group entries under a collapsible level. Enter/Right descends, Esc/Left goes back. Nest up to 8 levels.

submenu "CachyOS" {
    icon=arch

    menuentry "linux-cachyos" {
        type=linux
        vmlinuz=/vmlinuz-linux-cachyos
        initrd=/initramfs-linux-cachyos.img
        cmdline="root=UUID=xxxx-xxxx rw"
        icon=arch
    }

    submenu "Snapshot 906" {
        menuentry "linux-cachyos (906)" {
            type=linux
            vmlinuz=/vmlinuz-linux-cachyos
            initrd=/initramfs-linux-cachyos.img
            cmdline="root=UUID=xxxx-xxxx rw rootflags=subvol=/@/.snapshots/906/snapshot"
            icon=safe
        }
    }
}

Only icon= is accepted inside a submenu block. A } closes the innermost open block. With the above, default=CachyOS/linux-cachyos auto-boots the child entry.

Widget / Button Appearance

All prefixed btn_ or ui_. Omit any to inherit the built-in look.

Window Chrome Overrides

Override individual aspects of the window skin. Any key omitted inherits the skin/theme.

Validation and Error Handling

Parser tolerance:

• Malformed lines are skipped; parsing continues.
• Unknown keys are silently ignored.
• Missing closing quotes are tolerated (runs to EOF/newline).
• Empty/partial configs produce a bootable menu with defaults.
• If forebo.cfg is missing, a hardcoded 8-entry default config is used.

Fallback rules:

Complete Example

# Global
timeout=30
default=0
remember_last=1
background=/forebo/bg.bmp
theme=forest
menu_style=classic
menu_selection=doublebar
menu_show_icons=1
pcspeaker=0

# Forest OS
menuentry "Forest OS" {
    type=forest
    kernel=/forebo/kernel.elf
    module=/forebo/initrd.tar
    icon=os
    cmdline=""
}

# Linux
menuentry "Linux" {
    type=linux
    vmlinuz=/forebo/vmlinuz
    initrd=/forebo/initrd.img
    cmdline="root=/dev/sda2 ro quiet"
    icon=tux
}

# Chainload
menuentry "Chainload GRUB" {
    type=chainload
    chain=/EFI/BOOT/BOOTX64.EFI
    icon=grub
}

# Submenu
submenu "CachyOS" {
    icon=arch
    menuentry "linux-cachyos" {
        type=linux
        vmlinuz=/vmlinuz-linux-cachyos
        initrd=/initramfs-linux-cachyos.img
        cmdline="root=UUID=xxxx-xxxx rw"
        icon=arch
    }
}

# Tools
menuentry "ForeB Shell"   { type=shell    icon=terminal }
menuentry "Recovery"      { type=recovery icon=gear }
menuentry "Tools"         { type=tools    icon=gear }
menuentry "Settings"      { type=settings icon=gear }
menuentry "Firmware"      { type=setup    icon=settings }
menuentry "Reboot"        { type=reboot   icon=reboot }

ESP File Layout

/forebo/
  forebo.cfg              Configuration file
  kernel.elf              Forest OS kernel (Multiboot1)
  initrd.tar              Forest OS initrd
  bg.bmp                  Menu background image
  vmlinuz                 Linux kernel (optional)
  initrd.img              Linux initramfs (optional)
  icons/                  Per-entry icons (TGA)