Sometimes, your device has limited access (no keyboard, network, etc … ), and we need to update eMMC storage content automatically. What did we need? Just prepare a special removable disk

• write OOWOW system image to removable device
• create dump image for eMMC by any way fox example from oowow or manually by hands
• create autoinstall config

• Plug prepared removable disk into your device
• Reboot into OOWOW mode by any way - just reset your device if it can boot up from this removable disk or by a special shortcut or i2c command if device has embedded oowow
• Wait for autoinstallation, all processes must go automatically
• Reboot to upgraded system

BOARD.*.emmc.img.zst put into root on 2n SD partition with label dump

Stored into rescue/config/autoinstall on 1st SD partition with label rescue

/config/autoinstall

BOARD.image_name[.BYTES-bytes].img.[zst|gz] [-sBYTES] [-r]
 
# BOARD         board name [ VIM1 | VIM2 | VIM3 | VIM3L |  Edge | Edge2 | VIM1S | VIM4 ]
# .BYTES-bytes   write size limitation tag
# -sBYTES       write size limitation parameter
# -r            resize fs parameter

/config/autoinstall

VIM3.hg_1.0.emmc.img.zst

/config/autoinstall

VIM3.hg_1.0.emmc.img.zst -s15634268160

/config/autoinstall

VIM3.hg_1.0.emmc.img.zst -s15634268160 -r 

/config/autoinstall

VIM3.hg_1.0.15634268160-bytes.emmc.img.zst -r 

edit-and-save-auto-install-config

~$ echo VIM3.hg_1.0.emmc.img.zst -s15634268160 > /config/autoinstall
~$ krescue.configs -s

print-auto-intall-config

~$ krescue.configs -p | grep autoinstall
config_autoinstall="VIM3.hg_1.0.emmc.img.zst -s15634268160"

display-auto-intall-config

~$ cat /config/autoinstall
VIM3.hg_1.0.emmc.img.zst -s15634268160

disable-autoinstall

~$ rm /config/autoinstall && krescue.config -s 

can write only 11100000000 bytes for example

check.sh

tail -c+11100000000 VIM3.hg_1.0.emmc.img | hexdump -C

resiez_root_fs.sh

root@localhost:~# df /
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/rootfs     14779408 5847484   8741216  41% /
 
root@localhost:~# resize2fs /dev/rootfs 
resize2fs 1.45.5 (07-Jan-2020)
Filesystem at /dev/rootfs is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 2
The filesystem on /dev/rootfs is now 7587840 (4k) blocks long.
 
root@localhost:~# df /
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/rootfs     29808700 5848092  23618452  20% /

Another way create installation disk by script

example

DISK=/dev/sda ./autoinstall edge2-armbian-bookworm-legacy-minimal.img.xz

autoinstall-disk-create

#!/bin/sh
 
#= USAGE: DISK=/dev/sdX ./autoinstall-disk-create [IMAGE]
 
DISK=${DISK:-/dev/sda}
IMAGE=${IMAGE:-$1}
 
FAIL(){
    echo "[fail] $@">&2
    exit 1
}
CMD(){
    echo "# $@">&2
    sudo "$@" || FAIL
}
 
[ -s "$IMAGE" ] || FAIL "image undefined"
 
# create parts
cat <<EOF | CMD sfdisk $DISK
label: dos
1 : start=       24576, size=      106496, type=e
2 : start=      131072, type=7
EOF
 
P1=${DISK}1
P2=${DISK}2
# format partiotions
CMD mkfs.vfat -n rescue -i DEADBEEF $P1
CMD mkfs.exfat -n dumps $P2
 
CMD mkdir -p /tmp/dump /tmp/rescue
# copy image
 
CMD mount $P2 /tmp/dump
CMD cp $IMAGE /tmp/dump
 
ls -l1 /tmp/dump
 
# create config
CMD mount $P1 /tmp/rescue
C=/tmp/rescue/rescue/config
CMD mkdir -p $C
echo $IMAGE | CMD tee $C/autoinstall
 
CMD umount $P1 $P2
 
echo DONE