Upgrade path

[benhylau]

The SD card is a MBR disk containing at least one FAT partition:

• Some unpartitioned space before the first partition contains uboot and some allwinner stuff
• The FAT partition contains:
  • conf.d/ (configs)
  • boot/ (everything else)

To upgrade the node software, the user can mount the FAT filesystem on a computer, then drag-and-drop replace:

• The kernel zImage or other components in boot/
• Drop custom configs into conf.d/

In the rare case that the bootloader (uboot being not in the FAT filesystem) needs to be upgraded, the user can back-up conf.d then reflash the SD card, and drop the backed up config directory into the new FAT filesystem.

[benhylau]

@hamishcoleman Perhaps you can elaborate on the OTA upgrade addition, and its self-recovery mechanism based on an incrementing counter of failed boots?

[darkdrgn2k]

In the rare case that the bootloader (uboot being not in the FAT filesystem) needs to be upgraded, the user can back-up conf.d then reflash the SD card, and drop the backed up config directory into the new FAT filesystem.

Thought:

Could we create a DD file with just the boot loader and not the root partition. That way the bootloader is seperate from the full flash image. (Kind of like what you see CISCO do with them ROMON boot loader)

That way you just flash the dd to the card and the partition does not get overwritten (as long as the partition tables are not part of that image!

[darkdrgn2k]

From what I learned I think that on ram disk uInitrd holds the root filesystem. Simply replacing it (assuming no kernel modifications etc) would be enough