Hi,
After bricking my unit with bad firmware supplied by Xtrons to solve an audio issue, I was able to identify the manufacturer and was fortunately successful in obtaining the correct firmware for my unit.
I must say that both Xtrons and the manufacturer were extremely helpful, with HanSong delivering the result following supplying 3 iterations of firmware.

The TD699G was purchased in Dec 2015:
UI:
Version:
DVD Version: C07-08 MCUVER: hanSong150714FA---C
System: Windows CE 6.0
BootVer: M3-265M-150801-08-B-V1.0.0
OSVER: M3-265M-150801-08-CE6-V1.0.0
APPVER: 20150723-Ver1.1.1-HZC_2531_UI23_MT_ZY
Flashsize: 256M
UUID 00EC7472-D9A2-3835-3336-303805050C0E

Notes from my experience:
1. Use the 4GB SDCard supplied with the unit, [FAT] formatted and named [SDCARD]
2. Copy the file [UPD] to the SDCARD first, then the remaining files
3. Insert the SDCARD into the [MAPS] slot and power on. Wait for the flash/app upgrade to complete, approx 3 minutes.
4. If the update completed successfully, you will be presented with the display calibration screen. Calibrate the display
5. Factory settings - configure your unit appropriately in the hidden menu [when in main menu,long press the TIME on left. TD699G then will enter the factory setting interface, click next page, close the selectGPS option,then press the power button to shut down the unit - do not remove power. This last step applies factory settings and configures the unit for GPS. Review other settings.

While I have included all firmware supplied, the firmware that restored my unit is [升级APP-2015.12.12-works.RAR]
Firmware:

I hope this helps someone, as this forum has been extremely helpful to me, as was HanSong - the techsupport received from Michael Mao was very helpful.

- machcnz