Thread: Alternative firmware fo kenwood dnx520vbt

Assuming that you've used the right boot.bin, GARMIN screen means that the bootloader is sill working, and the pre-boot mode should be still available. The only problem is that we don't know how to enter it.

Originally Posted by jpnos

The system above for my equipment is for pre-boot for radio system.

Do I understand you correctly that FUNCTION + EJECT puts the radio system into pre-boot mode?

Originally Posted by jpnos

I tested in order to put on sd GUPDATE:GCD and update xrgn to reload my backup
Any idea ?

GUPDATE.GCD update and update.txt execution are initiated by the firmware, which is not working right. So both ways are not going to work.

So, you should find a way to enter pre-boot mode. You could do some googling, or pressing other button combinations (like all combinations of 2 buttons, 3 buttons, etc).
Also make sure USB drivers are installed on your PC (but as I understand, you've already updated this device through USB, when it was showing "SYSTEM SOFTWARE MISSING", so they are already installed).

Alexander2010 says that you can't put it into pre-boot mode by pressing buttons on the front panel, and instead you need to disassemble it and connect some pins on the motherboard.
So if you can't find another way to enter pre-boot mode, then the only way is to disassemble the navi module. If you send here a photo of the motherboard, Alexander2010 will tell you what pins to connect exactly.

UPD:
Also I want to explain why pre-boot mode was available when "SYSTEM SOFTWARE MISSING" was show on the screen. It's because the bootloader enters pre-boot mode automatically when the firmware is wrong. In your case the firmware has had wrong loading address and due to this HWID test failed.