Linux-factory-reset

scripts used in factory reset, partition auto clonning

Why

• Have the device reset to a known good factory image
• Image is corrupted, reset-to-factory it and recover it.

Quick sollution for small images

• Identical images on 2 partitions. When system boots from seconds partition it replicates itself.

Alternative for larger image that wont fit on both partitions

• You can have in second partiton a minimal linux ~200M like the one here: https://github.com/circinusX1/minimarmfs

• Have the rootfs tar.gz-ed

• Change the installation script to untar, instead of sync like:

  tar --checkpoint=.1024 --checkpoint-action=exec=/bin/sync --warning=no-timestamp -xhpf ${TARFILE} -C ${FACT_D}/

How:

• By holoding a GPIO down for 10 seconds after Reset or on Power On it initiates a factory reset.

• Make u-boot changes. The changes makes u-boot to boot from second partiton than the default one

  • I did it for iMX6 and Beaglebone.
  • iMX6 would boot from <block_device>p3 instead <block_device>p2 when GPIO 120 is LOW.
    • (default is down, pull it up with a resistor)
  • am335 would boot from <block_device>p2 instead <block_device>p1 when GPIO 48 is LOW

• Partition the Sdcard or eMMC with the partitioning script.

  • Will create an extra one more partittion on remainig space (/data)
    • (give some 500M by configuration) for /var/log and /usr/share
    • Will reduce writes to / and peserve it in case of accidental power intrerruptions
  • Edit and make changes according to your eMMC size and Linux image size.
  • Tweak the % so the image would fit in P1 and P2, respectevily P3 (imx)

• Put same stock image on LIVE and FACT.

  • You can put it on fact only then reboot and hld the gpio down, will replicate itself to P1.
  • LIVE for Beaglebone would be P1 and for iMX P2
  • FACT for Beaglebone would be P2 and for iMX P3

• Configure the clonning script so it exist when image boots from LIVE (P1-am335 P2-iMX6ull)

• Enable the service on both or on factory only. Make it to call the clonning script.

• Test it

imx6 The eMMC is parttioned as follow

[50M free] P1(boot / FAT) 2-live 3-fact 4-data

• imx5 u-boot chnages patch to boot from P3 when GPIO 120 is Down. * By default is down so it has to be pulled up to boot from P2 * It also boots to factory if a file in /P1 called bootfact exists.

am335 (beaglebone) The emmc is partitionned [50M free] P1-root-live P2-facr p3-data

• the u-boot patch has also the am335 patches but look for MCO_*. That makes BBB to boot from P2 when GPIO 48 is LOW