GP2X black screen only + JTAG advice

Discussion in 'General Talk' started by slaanesh, Feb 27, 2016.

  1. slaanesh

    slaanesh Certified Guru

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    I bought a second hand GP2X which was in pretty average condition. It booted into Fireware 3.0 but it didn't actually do anything. ie. get into the gp2xmenu.

    The SD card was difficult to insert, so I disassembled it and found a piece of rubber in the SD card holder. During this the SD card hold literally sprang apart, I recovered the spring and the diagonal gadget which ensures the SD card is inserted the correct orientation.

    Anyway, I put in my 256MB SD card with Firmware 2.12 and tried to re-flash however it just say at the "firmware upgrading" screen for ages, not progressing. SO I switched it off and now it only boots to a black screen.

    According to unbricking guides the black screen isn't fatal but it doesn't seem to be able to go back into the firmware upgrading screen when booting with SELECT+START depressed.

    Can someone tell me at what bricked stage this GP2X is in? I would buy a JTAG to repair it properly as it would be useful possibly for other handhelds I have. What JTAG is recommended to be used with a GP2X?

    Oh Yeah, the SD Card. A little bit is missing and it no longer will allow the card to sit in place. I could remove the spring mechanism I guess but I like to find the missing bit. What does it look like? Is it a little metal rod about 10mm in length with a little kink?
     
    Last edited: Feb 27, 2016
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  2. Amethyst

    Amethyst Member

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    To flash fimware v2.1.2 you should have a base firmware of v2.0.0. Firmware v2.1.0, v2.1.1 and v2.1.2 are updates for v2.0.0. Try again, but with the v2.0.0 firmware. Is the GP2X logo appearing on the black screen on boot? Mine was when one of my GP2X's screwed up when downgrading from v4.0.0 to v2.0.0. The only thing that helped rescue it was the nand blanker on the archive. It worked a treat

    http://dl.openhandhelds.org/cgi-bin/gp2x.cgi?0,0,0,0,42,2490

    But make sure that SD is sat right. It sounds like it may have unseated during the flash. One of my GP2x's I got cheap had similar problems with it's SD slot. I ended up permanently glueing a Micro SD Apapter into the SD slot. Now I can only use Micro SD cards on this unit, but it works really well. I just pull them out with my nail.

    If your unit does need a Jtag, the break-out-board or cradle is the easiest way to rescue it. There is some info here which may help you determine the extent to which it is bricked:

    http://wiki.gp2x.org/articles/u/n/b/Unbrick_Your_GP2X.html

    http://www.distant-earth.com/gp2x/2005/11/howto-unbrick-most-bricked-gp2xs.html

    http://www.oneandoneis2.com/linux/GP2X/unbrick.htm
     
  3. slaanesh

    slaanesh Certified Guru

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    First off - thanks for replying!
    I have no logo ... Just black screen. I thought I read that this meant it was bricked. Could you confirm that is correct?
    I do have a cradle which I see has a parallel interface with JTAG connections. It looks like modern JTAG devices available on eBay don't directly support this pin out but it would be easy to wire one up. Can you recommend a cheap unit that will do what I need and function with OpenOCD?

    Sent from my Nexus 7 using Tapatalk
     
  4. Amethyst

    Amethyst Member

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    If it's black screening with no logo it looks like it is bricked. But your bootloader should still be intact. Flashing firmware v2.1.2 over v3.0.0 should not have ruined the bootloader. You have the cradle so it should be straight forward. No need to purchase another Jtag as the cradle is wiggler compatible (if Openocd is needed for the U-boot). Use a fully wired parallel (DB25) cable. Download the Breakout board Jtag software linked below. It will work with the cradle as they are pretty much the same thing apart from some power revisions (the BoB uses the same 3.3v (-) polarity PSU as the GP2X, whereas the cradle uses a 5v (+) polarity PSU). Go from section 5 in the pdf manual. Make sure your cradle is powered by the PSU (I know this might sound daft, but some GP2X's throw 5v out of the EXT port and can actually power the cradle if the batteries are good enough). Also make sure you have a fully charged decent set of batteries in the GP2X, and the files from firmware v2.0.0 are on the root of the SD card.

    http://dl.openhandhelds.org/cgi-bin/gp2x.cgi?0,0,0,0,23,1626

    If for some reason the bootloader has been corrupted, use Openocd with your cradle. Instructions and U-boot are below:

    http://wiki.gp2x.org/articles/u/n/b/Unbrick_Your_GP2X_With_Openocd.html#

    http://dl.openhandhelds.org/cgi-bin/gp2x.cgi?0,0,0,0,64,1562

    Good luck with it.
     
  5. slaanesh

    slaanesh Certified Guru

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    Thanks for the detailed response again!

    I didn't realize that the cradle included a JTAG.

    My next problem is that I don't have a PC that has a parallel port anymore. I gave up on PC hardware years ago and only have Macintosh hardware at home and PCs without parallel ports.

    The must be a way of connecting it to a USB port?

    I have a power adapter, but do I really need to use batteries in the GP2X and power the cradle at the same time? I thought the cradle powered the GP2X?
     
  6. notaz

    notaz Certified Guru

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    I used to be able to reflash the bootloader (with an interface board) and still have a PC with parallel port, so in the worst case I could probably dig it all out (it's all stashed away somewhere right now).
     
  7. Amethyst

    Amethyst Member

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    You're welcome.
    That's a shame you haven't got access to a parallel port, you only need it for a few minutes. I keep an old PC stored away in case I ever need a serial or parallel port. You could try one of those USB to Parallel 25 pin adaptors (linked below) but I couldn't guarantee it would work:

    http://www.ebay.com.au/itm/1M-USB-t...pter-Converter-Windows-8-7-/121864912394?hash

    With regards to using batteries as well as the PSU on the cradle, yes you need batteries inserted too. The GP2X still needs it's own power supply (whether it be a GP2X PSU or batteries) even when it's sat in the cradle. If you look at the Jtag pic in the PDF, it shows both the BoB PSU and the GP2X PSU connected simultaneously, but a freshly charged good set of batteries will suffice.
     
    Last edited: Feb 29, 2016
  8. slaanesh

    slaanesh Certified Guru

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    Okay I've got myself a laptop with a parallel port and serial port.
    Connected everything together. Hooray.
    It's a Windows XP machine, which is fine.
    Now, I connected my good GP2X to the cradle then serial to laptop and booted. Serial settings 115200 8N1 Xon/Xoff and hey presto, I get serial output. Great. This at least confirms that is working fine.

    Next is the bad GP2X. Start it up, nothing from serial. I assume this is normal.
    Connect JTAG port to parallel and fire up OpenOCD just after I switch on the GP2X. Okay, problems here.

    Which version of OpenOCD do I use? I'm trying to use this script for OpenOCD but I get errors parsing the config file. I've tried 0.9.0 then 0.4.0, 0.3.0 and 0.2.0. None of them parse the file correctly though the lower two versions seem to do a better job as they fail lower down in the config file at the following line:

    #target configuration
    daemon_startup attach
     
  9. slaanesh

    slaanesh Certified Guru

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  10. Linux-SWAT

    Linux-SWAT Hardcore Member

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  11. slaanesh

    slaanesh Certified Guru

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    So here's a summary to unbrick your GP2X using the cradle and JTAG software:

    Hardware:
    • PC running Windows and a parallel port and serial port. I specially bought an old laptop (Toshiba Satellite 1800) for $25.00 to do this. It's pretty neat has parallel and serial port as well as USB, ethernet and WIFI so plenty of connectivity options. Make sure the parallel port is set to a non-ECP mode. This needs to be done from the BIOS.
    • GP2X that needs resurrection. Mine wasn't starting up. There was no boot screen, just black.
    • GP2X cradle. I bought mine ages ago, haven't used it a lot.
    • Parallel port cable with male and female pins - all connected. I had all the bits for this so soldered up my own cable.
    • Serial cable - 9 pin version.
    • Power supply for GP2X. I bought this ages ago originally for the GP32 but the same one is compatible for the GP2X.

    Software:
    • GP2X JTAG software (this runs on Windows only, no issues with Win XP).
    • Terminal software (I used HyperTerminal, comes with Win XP) with COM1 set to 115200 8N1 Xon/Xoff.
    • CMD shell (comes with WinXP).

    The guide above explains what to do but it's pretty straight forward.

    Connect the parallel cable to computer and the cradle. Connect the serial cable to computer and cradle. Slot the GP2X into the cradle. Power into the GP2X with power supply. My GP2X was an F-100(B) so this also powers the cradle no problem for this procedure.

    Start the computer. Extract the GP2X JTAG software and have it ready. Start Terminal software to monitor activity. Start CMD prompt. Power up GP2X. Run the GP2X JTAG software. Watch the GP2X JTAG software do it's thing. And that's it. Wait until it's finished and switch it off and then follow the normal flashing procedure as u-boot should now be resurrected.

    I flashed 2.0 BIOS first and then upgraded to 2.1.2 which is find for my needs. The newly resurrected GP2X is now my dev unit as it's slightly more overclockable than my other unit.

    If anyone else wants their GP2X brought back from the dead send me a message. You can send me your GP2X and pay for return postage and I can fix it for you.
     
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