Support dual bootloader (#27)

* Support dual bootloader

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>

* Make ova running

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>

* fix uboot

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>

* Update supervisor

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>

* Support all rpi

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>

buildroot-external/rootfs-overlay/etc/rauc/system.conf

@@ -2,7 +2,7 @@
 compatible=%COMPATIBLE%
 mountprefix=/run/rauc
 statusfile=/mnt/data/rauc.db
-bootloader=barebox
+bootloader=%BOOTLOADER%
 
 [keyring]
 path=/etc/rauc/keyring.pem
@@ -10,14 +10,24 @@ path=/etc/rauc/keyring.pem
 [slot.boot.0]
 device=/dev/disk/by-partuuid/b3dd0952-733c-4c88-8cba-cab9b8b4377f
 type=vfs
-bootname=boot
+
+[slot.kernel.0]
+device=/dev/disk/by-partuuid/26700fc6-b0bc-4ccf-9837-ea1a4cba3e65
+type=ext4
+bootname=A
+
+[slot.kernel.1]
+device=/dev/disk/by-partuuid/fc02a4f0-5350-406f-93a2-56cbed636b5f
+type=ext4
+bootname=B
 
 [slot.rootfs.0]
 device=/dev/disk/by-partuuid/8d3d53e3-6d49-4c38-8349-aff6859e82fd
 type=raw
-bootname=system0
+parent=kernel.0
 
 [slot.rootfs.1]
 device=/dev/disk/by-partuuid/a3ec664e-32ce-4665-95ea-7ae90ce9aa20
 type=raw
-bootname=system1
+parent=kernel.1
+