In place upgrades? Like OpenWrt

[Ratatui]

I have to use a custom Ubuntu OS on these devices and need to use eMMC rather than SD cards.
Most of these devices will be remote to me and updating parts of the OS is difficult.
It would be easier to send each device an OS update but I'm not sure how that could be done.

On OpenWrt for example, it's as simple as uploading the new image to the device then using sysupgrade/mtd to write the new image. When the device boots, the new image does too.

The devices will be running from eMMC and I've not found any information that says I can do in-place flashing.
The only way I can think of is to partition with a partition I can use to store the image then use some sort of tool to flash the existing OS that's running on the eMMC.

Does anyone have any ideas how this could be done?

[Gribladeen]

One approach is to set up a dual-partition system on the eMMC. You can have two separate partitions: one for the active OS and another for storing the updated OS image. The active OS partition would be running while the update is being prepared and stored in the secondary partition. Once the update is ready, you can use a tool to switch the boot configuration to the updated partition, effectively booting into the new OS on the next reboot. This approach ensures a smooth transition without disrupting the device's operation.