I suppose I should have thought about it and made my file "BackupMenu.item" instead of "backupmenu.item" so it'd overwrite and force this version instead... But I wasn't thinking.
As its just a one-line launcher in this version, I'll make my next release with two copies of that file, so it'd overwrite. At least, until I get it built for extras-devel to replace the old version.

The one in the repo works fine on 50-80% of N900s. On the others, it will backup properly, but not restore due to bad blocks on the rootfs NAND. The problem is, that version uses DD to make a byte-for-byte image, which ignores bad blocks, and OneNAND flash doesn't "hide" bad blocks, unlike MMC/SD/harddisks do.
This version copies all the files using tar, then restores those as files. Because it works in files, bad blocks aren't an issue, and you can edit the resulting images if you want(say copy files out or apply a patch before restoring).

Yea, that's what it's supposed to be. It'd work anyway, though, provided you deleted the "/etc/bootmenu.d/BackupMenu.item" file.
Yup, just make sure you can flash that rootfs image and it'll work.
(I had an odd version of mtd-utils on my desktop. It'd make images, say it was done. The images were the right size, I'd flash it... And it wouldn't mount on the N900).

I figured, though, that you'd probably have your N900 "bricked" due to a failed backup, and want to use your desktop to make the image and flash it. If you have the foresight to make the image first, that's always a good thing.

Now, eventually, I intend to both A, have an option to gzip the image, and B, an option to make a flashable image right there from BackupMenu. A would make the images smaller, but take longer. B would be useful, but take an extra 256mb of space.