I found a different copy of this file hosted here
which I did manage to download ok. This is just the flasher and updated code for WM6 for the SPL G3. I sourced it from here
which is the google translation of Chinese original here
I tried to use the flash updater but it told me I already had the same or higher version in the phone and aborted, so I formatted a memory card and put WMIPL.DIP and WMUPDAT. DIP in the root, then powered on by holding the 6 button and tapping the power button. As I described previously this showed a blue empty box which gradually filled from left to right. Once it had filled it re-powered.
For the good news, it worked fine and appears to be quicker than WM5 but for the bad news, most of the ROM is in Chinese. The initial boot up sequence where the wizard pops up to setup mail is in Chinese. Once you've got into the phone proper, you can press start, 9, 0, 2 to get into regional settings and drop down the top box to find "US English", use the left soft key to confirm. It pops up a dialogue box (you must reboot to take settings). Then reboot and when it comes up the vast majority is then in English, you can then go back in to select UK English in that same menu.
The "about" screen says "i-mate SPL G3 software version TF_WM6_SPL_i_mate_VER_03.09_S0805151818(13.13)". It has a "windows update" option which might bring something else to the party.
The vast majority of it from here is then in English and WM5torage is installed in the ROM, however other bundled software such as Celetask, Resco Explorer 2007, Regedit are in Chinese and I've not worked out how T9 works now but I think this is more a WM6 strangeness (seems you have to complete the word with * before pressing # for a space). The calculator makes use of the directional buttons for functions and =. Word, Excel and Powerpoint mobile are present.
I look forward to the official release from i-mate with interest, though the SPL is still left for dead by the Nokia E51 I bought to replace it.