Eolair posted on Dec 17 2005 at 12:03 PM said:
If this happens to me I'm going to be PRETTY upset. Is GPH aware of this bug? Has it been reported? Is it addressed in any of the firmware updates? I really dislike the lack of information coming from GPH. This is a major bug that bricks the unit and if they haven't fixed yet it they need to do it ASAP <_<
You're absolutely right. I don't know for sure but GPH is most probably aware of this.
I've been looking into a way to flash the GP2X using JTAG. Here's what I have so far.
-All the buzz is about getting a JTAG cable, however the cable is easy to make. Dygnsys (they build the MMSP2 dev boards
used by GPH) use a macraigor compatible cable (info from their website). Schematics for those are available on the web. The JTAG pinout (on the GP2X ext connector) is available from the wiki. (If it is correct.)
-So we need software. This is far more difficult as the JTAG standard only specifies the connection and a few (2) commands, the other commands are chip specific. Unfortunately the specs are not publicly available. I do not know if the Samsung NAND flash chip has a direct JTAG interface or if the JTAG interface is only connected to the MMSP2 which is then used to access the NAND. On the Dignsys I read that they ship their JTAG probe with GDB. (A GPLed software debugger which
can be used to communicate with some devices via JTAG.) GDB does not support flash chips, but Dignsys said the following to me in an e-mail: "The JTAGProbe is our product that sales with Wiggller Compatible hardware equipment with simple
flash upgrade tool.". I can't really draw a conclusion based on that info about which method to access the NAND is used.
-Dignsys sells their JTAG probe with software for $50,-. However the shipping from Korea is very expensive.
-I've asked GBAX when they will have a JTAG cable (and software) and whether it will be for sale, however they have not yet responded.
-On the GP2X forum I just read the following: "I just wanted to let everyone know that I have spoken with Dynamism and they are getting specifics on stocking JTAG cables. If you are looking for one, Dynamism should have them soon.".
So, I've been thinking about buying a cable from Dignsys. I will definitely do so if I break my GP2x. However I find it rather expensive to do so just to attempt to help the community. (The goal of buying one is just to check out
their software part so people can (possibly) build their own cable and reflash their unit.) Also I don't want to check things with my working unit. I have not yet contacted GPH about this.
What do you think? Any ideas?