Well, according to my source, dialects differ quite widely in China, but written chinese is pretty much the same all over. Having spoken with said source, I'm 95% certain I can get it translated into english. Graphics on the pages might need to be re-done, but I know a guy who could do that for me too !! Not sure if my skills extend to Jtagging it and getting the firmware off it, but I am meant to be an electronics engineer so I guess it shouldn't be too difficult once I've researched what I've gotta do !
For this job, the UART serial access is the best method. JTAG is used as little as possible because it's so slow. The bus speed is slow and its got a heavy overhead. It's very useful for transferring a bootloader (usually 64kBytes or less) - just so you can get enough code running on the device to support a serial port transfer or a minimal network stack, to allow for faster data transfer.
But for transfering an entire NAND flash image, JTAG can literally take hours. I'm working on a JTAG tool to re-program the BT Business Hub and the best that can be squeezed out of the JTAG programmer is 12kBytes/sec.. The (2Wire) BT Business Hubs have a whopping 32MByte NAND flash IC which would take the best part of an hour to re-program by JTAG.
Just need to get my hands on one now 
Its faintly possible I could get my translator to ship one over for me, but it depends on where she is currently. I'll have to find out. Failing that, I'll have to have a go at sourcing one myself which could be tricky, but at least I can contact someone who can read the original pages and regularly moves stuff between the UK and Singapore. She's abroad at the moment but will most likely be back in the UK in a month or so. I'll sound out the possibility of her bringing one back for me, failing that, I'll get her to help me source one over the net.
There are a few secondhand DB120-B2+ VDSL2 modem-routers listed for sale at £13 (130 yuan) in mainland China. Enough money to spend initially, perhaps. The risk is that the flash file system (FFS) of the device is locked like the FFS of the Huawei and ECI have been...
There are also Huawei HG622 for sale for £16+ (160 yuan).
http://item.taobao.com/item.htm?id=14799664113These look nothing like the HG612, but have the same VDSL2 chipset, as well as 802.11n wi-fi and 4 ethernet ports, and they have a USB port with a kernel driver for a 3G dongle.
The user interface of this HG622 appears to be English, which would make things a lot easier.. The HG622 is the FTTC CPE used by Pakistan Telecom (PTCL) and in Spain by JazzTel.
cheers, a
