Unbrick Your GP2X With Openocd
Here, we describe how to setup and use openocd/GDB to load a RAM version of U-boot by JTAG. This is a part of the unbricking process for the GP2X. The software used here works well on UNIX OSes, like GNU/Linux. I don't know if it is possible to use this on windows.
The easiest way to get openocd is to get the packages for your distro. For ubuntu/debian, it is called openocd. Or, you can download and compile it.
GDB for ARM
It is quite easy to build GDB :
$ cd gdb-6.6 $ mkdir build $ ./configure --prefix=$PWD/build --target=arm-elf $ make && make install
Then you can launch it with :
Here is the configuration of openocd (gp2x.cfg) :
#daemon configuration telnet_port 4444 gdb_port 3333 #interface interface parport parport_port 0 parport_cable wiggler jtag_speed 0 #use combined on interfaces or targets that can't set TRST/SRST separately reset_config trst_and_srst srst_pulls_trst #jtag scan chain #format L IRC IRCM IDCODE (Length, IR Capture, IR Capture Mask, IDCODE) jtag_device 4 0x1 0xf 0xe #target configuration daemon_startup attach #target <type> <endianess> <reset mode> target arm9tdmi little run_and_halt 0 arm920t working_area 0 0x200000 0x4000 backup run_and_halt_time 0 30
To get access to parallel port under linux, you have to load some modules and fix access rights :
$ su # rmmod lp # modprobe ppdev # chmod 666 /dev/parport0 # exit $
- Plug the DB25 cable between the cradle and the parallel port of your PC.
- Plug power supply in the GP2X.
- Rack the GP2X in the cradle.
- Prepare the command line of openocd but don't hit enter : openocd -f gp2x.cfg
- Switch on the GP2X and launch openocd just at this moment.
- launch arm-elf-gdb in the directory where u-boot.elf is.
- issue the following commands :
exec-file u-boot.elf target remote localhost:3333 load