Sorry for reviving such an old thread (even though it is mine).

I haven't been able to revive my old N900 and bought a new one long time ago (and moved to Jolla since), but it still bugs me that this device is perfectly fine, just the USB port is broken and the system needs reflashing. So I had an idea... Any thoughts on the following plan?

1. boot NemoMobile from MicroSD (works fine)
2. chroot into Maemo (I think this worked as well)
3. install backupmenu in the chroot (this is the part I'm most worried about - it could break my access to U-Boot in the future, if I mess it up)
4. flash an image from backupmenu

I'm not sure if 3) can be done from chroot, but I can't see why not, if I mount all partitions.