Ok, new update.

I was able to reboot in recovery mode, after several full days trying without success.

The phone not being connected to USB:

1 - I removed the cover, removed the camera/flash cover to unplug the battery.

2 - I unplugged the battery

3 - left it unplugged when "drained" the cap by "jumping" the 2 connection of the power button with a screw driver for a minute or so.

3 - Then, I plugged the battery back

4 - with one screw driver I jumped the two right connection of the volUp button, then keeping the jump, I jumped th Power button connection for about 10s.

5 - the phone vibrated and rebooting in the Ubuntu Touch recovery

6 - plugged I was able to restart UBPorts flashing. All went well, the phone rebooted couple times itself and is now up and running Ubuntu Touch.