Hello and big thank you to Theking for his tutorials and links.
After much hesitation, I tried changing my tomtom navcore.
Tomtom navcore 7903 V2 with the original bootloader and 5.3029
I just put the navcore 8410 with bootloader 5.5122: result, the tomtom gets stuck on the boot picture and remains frozen despite resets!
I just changed the navcore through the 8302, the bootloader remains 5.5122 and tomtom starts and works except that I no longer have the voice radars!
I know it's not the right forum to ask for help but if anyone has encountered the problem mm, it would be nice to see me to find the radar
Thank you all