The bootloader

The bootloader is the software that will boot the Linux kernel, the core component of Lakka. Lakka uses the following bootloaders:

• syslinux / grub - on the PC
• bcm2835-bootloader - on Raspberry Pi
• u-boot - on other ARM boards

The booloader configuration file is generally present on the first partition of Lakka. It contains some useful settings that will be passed to the kernel. The name of this file differs depending on the platform:

• On Raspberry Pi - file name: cmdline.txt
• On the Generic PC - file name: syslinux.cfg and EFI/BOOT/grub.cfg
• On Amlogic devices - file name: uEnv.ini
• On iMX6 devices - file name: extlinux/extlinux.conf
• On Odroid-XU3/4 - file name: boot.ini

The name of the argument passed from the bootloader to the Linux kernel is called the cmdline.

Editing the cmdline

On Raspberry Pi

Edit cmdline.txt in the first partition of your SD card. This first partition is FAT32, so you can just plug the SD card in your PC to find that file.

The cmdline on RPi looks like this:

boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 quiet ssh vt.global_cursor_default=0 loglevel=2

On Generic PC

You can edit the files directly using a text editor, but also from your Lakka device, if you have access to the command line interface.

Remount the /flash mount r/w:

mount -o remount,rw /flash

Edit the two config files with nano:

nano /flash/syslinux.cfg
nano /flash/EFI/BOOT/syslinux.cfg

There are two files to support both BIOS and EFI boot.

In syslinux.cfg cmdline starts with APPEND, in grub.cfg with linux. There are two sections - Live and Installer, edit the cmdline in the Live section.

syslinux.cfg:

LABEL live
  KERNEL /KERNEL
  APPEND boot=UUID=1106-4449 disk=UUID=25c49e90-d6b6-4486-8c2c-12f15a6bef65 tty portable quiet

grub.cfg:

menuentry "Live" {
        search --set -f /KERNEL
        linux /KERNEL boot=UUID=1106-4449 disk=UUID=25c49e90-d6b6-4486-8c2c-12f15a6bef65 tty grub_portable quiet
}

On Amlogic

Edit uEnv.ini in the first partition of your SD card. The content of this file looks like this:

dtb_name=/dtb/meson-gxbb-odroidc2.dtb
bootargs=boot=UUID=1106-3535 disk=UUID=54c47770-0a4c-4295-a86b-f023c8026198 quiet console=ttyAML0,115200n8 console=tty0

On iMX6

Edit extlinux.conf in the extlinux folder on the first partition of your SD card. This first partition is FAT32, so you can just plug the SD card in your PC to find that file.

The content of extlinux.conf looks like this:

LABEL Lakka
  LINUX /KERNEL
  FDTDIR /
  APPEND boot=UUID=1106-5028 disk=UUID=1064beb8-b6ec-429c-aa98-c6adf4682c06 quiet video=HDMI-A-1:1920x1080@60

On Odroid-XU3/4

The file is named boot.ini on the first FAT32 partition. The line with cmdline looks like this:

setenv bootrootfs "boot=UUID=1106-5639 disk=UUID=4302d41d-14ae-4b70-9e4b-eb37825cf67d console=ttySAC2,115200n8 tty noram"

Below sections refer to legacy 2.3.x version, but are kept as reference

On Allwinner 20

The default uEnv.cb2 for Cubieboard2:

script=cubieboard2.bin
kernel=KERNEL
extraargs='console=ttyS0,115200 console=tty0 boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 rootwait quiet ssh loglevel=2 hdmi.audio=EDID:0 disp.screen0_output_mode=EDID:1280x1024p60 consoleblank=0'
boot_mmc=fatload mmc 0 0x43000000 ${script}; fatload mmc 0 0x48000000 ${kernel}; bootm 0x48000000

The default uEnv.ct for Cubietruck:

script=cubietruck.bin
kernel=KERNEL
extraargs='console=ttyS0,115200 console=tty0 boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 rootwait quiet ssh loglevel=2 hdmi.audio=EDID:0 disp.screen0_output_mode=EDID:1280x1024p60 consoleblank=0'
boot_mmc=fatload mmc 0 0x43000000 ${script}; fatload mmc 0 0x48000000 ${kernel}; bootm 0x48000000

On Odroid-C1

The file is named boot.ini on the first FAT32 partition:

ODROIDC-UBOOT-CONFIG

setenv bootargs "console=ttyS0,115200n8 boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 ro no_console_suspend vdaccfg=0xa000 logo=osd1,loaded,0x7900000,720p,full dmfc=3 cvbsmode=576cvbs hdmimode=1080p m_bpp=16 vout=hdmi ssh consoleblank=0"
fatload mmc 0:1 0x21000000 KERNEL
fatload mmc 0:1 0x21800000 meson8b_odroidc.dtb
fdt addr 21800000
bootm 0x21000000 - 0x21800000