I bought a used TomTom One 30 (PF244....).
Right from the start the tt booted with device configuration (language, time etc.)
After selecting voice, the tt rebooted and started over.

I flashed new software:
I did not format the drive but deleted all software.
Bootloader:5.5128
NC: 9.702 32mb_Version
some maps.
First boot:
The tt stooped booting, showing a screen (picture) with the icon of a sd card.
It seems the system can't read the boot loader.

What to do?
Any Idea is helpful.

I'm no expert so this is just a suggestion. Can you format the device and run a scan from the PC to check if the drive is damaged etc? Then connect to TomTom home and restore it to its latest, official navcore? If that works you should be able to patch maps from there to get you back up and running. I may be completely wrong but it gives you something to try until someone with more knowledge contributes. It's already broke so you've got nothing to lose. Good luck.

Sent from my SM-G950F using Tapatalk

Thanks for your help but it did not cure the problem.

I have formated the partition (2GByte internal) in Windows with SD-Formatter (no errors)
I turned to Linux and copied Bootloader 5.5128 (system) to the empty disk.
Than i added NC 9.702 to the disk.
I did this often before on TT One V1,2,3 and it worked always.
Starting the device: Shows picture of the screen and the icon of a SD-Card at lower left corner.
Normally i would see a yellow bar, showing the boot loader being loaded into memory but the One 125 does not do this.

Any idears?