2 considerations:
-I couldn't flash my dumped system (mmcblk2p10) partition. The T1 will continue failing to boot after SD recovery. Instead, I had to use the provided p10 partition in the standard SD rescue package.
The dumped data partition (p9) was succesfully flashed
-After resizing, I made a factory reset and a rooting to clean up things. After that, the T1 refuses to make updates and boots in recovery mode... fortunately updates can be made in this mode via usb gadget
.. Every day I discover a new behaviour :P