Installs grub[2] on boot partition on the system. In case GRUB2 is not available in the system, a fallback to Extlinux will happen. It's also possible to enforce the use of Extlinux by exporting a DIB_EXTLINUX variable to the environment.

Arguments

DIB_GRUB_TIMEOUT sets the grub menu timeout. It defaults to 5 seconds. Set this to 0 (no timeout) for fast boot times.
DIB_BOOTLOADER_DEFAULT_CMDLINE sets parameters that are appended to the GRUB_CMDLINE_LINUX_DEFAULT values in grub.cfg configuration. It defaults to nofb nomodeset gfxpayload=text.
DIB_BOOTLOADER_SERIAL_CONSOLE sets the serial device to be used as a console. It defaults to hvc0 for PowerPC, ttyAMA0,115200 for ARM64, otherwise ttyS0,115200.