Finalement c'est ce tuto qui fonctionne

rooter une samsung galaxy tab 2 avec windows

A tester sur un autre phone si cela fonctionne encore

Gné, le retrouvé plus. Au cas où je devrais formater à nouveau mon Samsung Ace Q aka Appeal.
Viens avec Android 2.3, la loose...

1-My phone is Roote possible you can try whit the phone not root and without sim card and you can also back up you file maybe.

2-check if your phone Go to dialer and type: *#7465625# look if you blocking network is ''on'' your phone is lock then clic ok

3-After Go to dialer and type:*#197328640# you have this is menu and touch de screen [1] DEBUG SCREEN

look Foto-1

4-After you have this is de menu and touch de screen [8] PHONE CONTROL

look Foto-2

5-After you have this is de menu and touch de screen [6] NETWORK LOCK

look Foto-3

6-After you have this is de menu and touch de screen [4]NW LOCK NV DATA INITIALIZE

look Foto-4 wait 1 of 2 min your screen freez

and after turn off your phone and restart your phone is unlock enjoy can now dialer and type*#7465625# and look de screen all off

and after you can Dialing *2767*3855# clear all locks!

tl;dr
via grub - e
linux /boot/vmlinuz-……. init=/bin/bash
mount -o remount,rw /dev/[partition root] /
passwd