hi hi everybody! thank you for your advice InsaneNutter! i am now on 13604 thanks to you. here is how i proceeded (may be it will help other people): 1) i made the update to 9199 using my ORIGINAL nand (not the one dumped by flash360, following your tuto :How to update your Jtagged Xbox 360 to Freeboot 0.032 (9199 Dash / Kernal) 2) i made a dump of the fresh flashed 9199 freeboot using nand flash. 3) i use the nand 9199 to update to 13604 (following your tuto : Easily update your Jtagged Xbox 360 to Kernel / Dashboard 13604 with FbBuild 0.33). 4) i flassh the new fresh flashed 13604 using nand flash. everything worked fisrt try ! just so awesome. just had one little problem (hope it won't happen again) : after i powered on my xbox, i wanted to plug my external usb drive (with all my games). so i turn my xbox off. i plugged the externed hdd drive and when i turned it on, i had the 3red leds and my screen was blue and purple. i though it was a nighmare and i turned it off. i took a deep breathe and waited 10 minutes, thinking what was this s**t. i turned it on again without the usb hdd and everything went back to normal. i was still in 13604. only then i plugged my usb hdd and launched xexloader and played to my games. hope this experience will help other.