Bought two of these from stoneswei on ebay (firmware TJC_9112_20, chip AK1025, memory Samsung 722). I have seen a few people on the forums request this firmware. They were hacked 1GB players sold as 8Gb. One worked for a few hours before giving a blue screen with the hour glass on it. The other lasted four weeks before doing the same. I sent back the first and the company sent back two! One of these then did the usual trick after 3 weeks.
I tried all the firmware on this site with MP3 tools 4.00 - no joy other than a white screen and behaving as an expensive memory stick! I tried stoneswei again (they seemed to dissappear for a while). They gave me a web address for a firmware loading tool + two firmware files -
http://www.ycibo.com/mp4help To get ProductTool_5_11_20070711 installed you have to change Regional and Language setting to Chinese and then once installed change back to English. It may take several tries to get the firmware to load! One player used one version of the firmware one player used the other. I also had to use the Dead Recovery Guide to force the ADFU server to run when one player was plugged into the USB. You do have to switch on then off then back on. But it works! Hope this helps someone.