Can past nandroid backups be broken by resizing partitions?

[ja2038]

Can past nandroid backups be broken by resizing partitions? If so, how does one restore a former partition size?

I have a series of nandroid backups for a device now several years old. Over time, various system updates to this device has changed the partition sizes, sometimes I gather, pretty dramatically.

Does partition resizing break those old nandroid backups?

Is there an easy way to figure out what the partition sizes were and repartition them?

 

[Hadron]

Are you certain that system updates have changed the partition sizes? That's not normal for most devices.

Resizing will certainly break a nandroid if the new partition were too small for the partition image. It shouldn't otherwise, though I should note that I've not changed a partition size for several years now.

 

[ja2038]

Are you certain that system updates have changed the partition sizes? That's not normal for most devices.

Resizing will certainly break a nandroid if the new partition were too small for the partition image. It shouldn't otherwise, though I should note that I've not changed a partition size for several years now.

Yeah, this is on a Moto E 2015, and it's clear from comments on various forums that at times Motorola increased the partition sizes between Android 5.0, 5.1, and 5.1.2 (or something like that.)

Anyway, you do seem to be confirming that nandroid restore doesn't restore partition sizes.

 

[Hadron]

No, a nandroid restore definitely does not change the partition sizes, it just restores data to a few of the partitions (boot, system, data, cache - it doesn't back up the lower-level firmware such as the baseband).

When I modified partition sizes on previous devices the procedure was to take a nandroid first, repartition, then restore the nandroid. This would have been self-defeating if the nandroid modified the partitions.

I'm surprised Motorola did that because it's potentially destructive of user's data, which manufacturers try to avoid with OTA updates. I suppose if they arrange it so that the cache partition is adjacent to the system partition and are prepared to shrink the cache that would be safe, but also has its limits. Most manufacturers simply start off with some free space in the original partitions to allow for the possibility that future updates may be larger.