CONFIGURATION

Kexecboot configuration

Kexecboot will try to mount all usable partitions and look for boot/boot.cfg
file on them. The stock Android distro is the only one configured by default,
and then you can add addtional boot.cfg files.

Note that the v3.0.8 stock kernel cannot read ext4 partitions formatted on
newer kernels unless metadata_csum flag is left out. So if formatting the
MMC card on your Linux PC, just do it with:

# mkfs.ext4 -O^metadata_csum,^64bit ...

You can have boot/boot.cfg and your Linux ARM distro on the same partition
that way, or set up a separate boot partition. Assuming you have boot.cfg
on mmcblk0p1, you should have something like this listed in boot.cfg file
on the micro-SD in boot directory:

LABEL=Linux on mmcblk0p1
PRIORITY=8
DTB=/boot/mainline/omap4-droid4-xt894.dtb
KERNEL=/boot/mainline/vmlinuz
CMDLINE=console=tty0 console=ttyS2,115200 fbcon=rotate:1 debug earlycon ro \
rootwait rootfstype=ext4 root=/dev/mmcblk0p1
TIMEOUT=3

And please note that any partition kexecboot tries to use must be unmounted
or else kexecboot can't use it. See kexecboot documentation for more
information on boot.cfg file:

https://github.com/kexecboot/kexecboot/blob/master/res/boot.cfg

If using older SafeStrap install, you can boot to the SafeStrap loopback
devices using the additional entries below. This mode is now deprecated as
we can boot to raw partitions without booting to Android first as described
in files PARTITIONS and INSTALL. For legacy support, the following should
still work though:

LABEL=SafeStrap rom-slot1
PRIORITY=10
DTB=/boot/rom-slot1/devtree
KERNEL=/boot/rom-slot1/kernel
INITRD=/boot/rom-slot1/ramdisk.img
CMDLINE="androidboot.safestrap.romslot=rom-slot1"
TIMEOUT=3

LABEL=SafeStrap rom-slot2
PRIORITY=9
DTB=/boot/rom-slot2/devtree
KERNEL=/boot/rom-slot2/kernel
INITRD=/boot/rom-slot2/ramdisk.img
CMDLINE="androidboot.safestrap.romslot=rom-slot2"
TIMEOUT=3

LABEL=SafeStrap recovery
PRIORITY=1
DTB=/boot/safestrap/kexec/devtree
KERNEL=/boot/safestrap/kexec/kernel
INITRD=/boot/safestrap/ramdisk-recovery.img
CMDLINE="androidboot.safestrap=recovery"

Note that there is currently nothing updating the kernels extracted from
rom slots if those kernels get updated and you have to update the kernels
manually.

For booting v3.0.8 legacy kernels, also SafeStrap atags file is needed in
the same directory with devtree file above. It can be found on the device
in /system/etc/kexec/atags and should be the same for all v3.0.8 based
kernels.