Thanks for your reply! I'd love to learn new things, I won't be bored.
just backed-up all the partition with dd, using minicom connected to /dev/ttyACM0 under Linux enviroment. All seemed ok so far. I'd love to understand the whole process, it'll make me feel more comfortable knowing "how does it work".
Many people claim wifi function doesn't work properly anymore after update firmware to 1.0.05. And I'm not sure I'll able to restore the device into pristine condition, i'm not sure what have the previous owner done with this t1 before you see. (yes, it's 2nd hand)