2.1.0.10 is now the first and only update step to take if you have to reset a Jolla tablet.
(Given your account is EA activated)
Mine lost some sectors resulting in only booting up half way and no apps were startable.
Corrected the error via disk check and did full reset in recovery and was running up to date 30 minutes later again.

Wow, didn't expect that. That's pretty nice to hear!

It should work like this on devices that use LVM for storage - IIRC (from reading the factory reset script a while ago) there is now a partition that holds the rootfs & initial home partition files in squashfs images.

When you perform a factory reset, the / and home LVs and the underlying VG will be dropped, then a new VG and new LVs for / and home created and formatted with EXT4. Then the rootfs squasfs is mounted and it's content copied to the rootfs lv, same thing for the initial home files.

Looks like this is the script in question, not sure if it still works the same way:
https://github.com/sailfishos/initrd-helpers/blob/master/factory-reset-lvm


In any case, this way you should be able to quite easily update the rootfs and home restore images - just add new squashfs files and delete the old ones (or possibly leave the previous pair, just in case).

Previously with btrfs a btrfs snapshot was used for factory reset - while this might have looked like a nice clean solution, you can't really update such a snapshot over network, especially if all storage is already allocated to the one btrfs instance...

Me neither.
I reseted a JP1 a month ago to 2.0.5.6 to give it to a (coding) friend and had to take all the expected 6(?) steps over the whole day with pita slow downloads.
I guess tablet being on 2.0.1.0 as revocery base helped, but i am sure i had steps between 2.0.x and 2.0.5.6 on jp1.
Tempting to try again now, also on C

Thanks, that cleared up much!!
And yes, judging from the output, the linked script was in action on my tablet during recovery.

updated aqua f*sh to official update 2.0.5.6 and then enabled developer mode, installed 2.1.0.9 update through terminal, patches , usb tethering and everything is working smooth. last time i had developer mode enabled store stopped working and there were no updates. ultimate statusbar patch and old pulley menu patch are not working and sharing multiple files through bluetooth is not working. i have some questions regarding updating through terminal but i guess i will learn with time.

Anybody else having spurious Sailfish Browser crashes on Jollas C since 2.1.0.9 ?

Relevant question on Together:

Browser crash when loading page (2.1.0.9+)

No as I do not have a Jolla C But I have had some on Jolla 1. More since the upgrade than before.

Happens much more often on Fairphone 2, despite having plenty of RAM

https://together.jolla.com/question/...tes-210iijoki/ now says:
The linked topic is temporarily not available and the date is next monday Also, I see no new update as of yet.

edit: I wrote "does not exist" instead of "is temporarily not available" previously, because apparently reading error messages is a bit above me today.

edit2: relates to "[2.1.0.10] Multiple crashes/lock ups per day since update" (google cache)

Yep. Especially JS heavy sites.