have bricked 900c? your 900c suddenly won't power on anymore? here's a solution

Well, say I'm not that expert on soldering jobs..and those metal parts on the mainboard to solder the jtag cables on are tiny

Gotta find someone who can do the soldering job for me
I'll let you know the result

you just solder on the pads under the CF slot, is this what you meant?

sorry cannot edit my first post, but IMPORTANT ADDITION I FORGOT TO SAY - even if you are using cygwin to do the jtagging, you have to copy the manufacturer files under usr\share\local\.


currently experimenting with jtagging the bootloader packaged in msbin, maybe there the erase is not buggy, then the instructions can be greatly simplified.


edit: right, msbin works perfectly. I'll soon make a new set of instructions, will be easier.

Edited by cmonex 2008-04-26 2:49 PM

A tip I learned from a Plumber: always clean your receptive parts with wire wool (it hurts!!!!)
Then always use Plumber's Flux,on both parties, it makes everything better lubricated & more likely to have a satisfying out-come!
Soldering is no real science.
Keep the recipients clean - wire-wool
Tin (make both recipients take solder)
& use flux - In my opinion - there's not enough in standard solder wire.
Best of luck
airhook

Edited by airhook 2008-04-26 7:10 PM

guide updated at http://hpcmonex.net/nec900/files/jtagging.html

but I'll copy it here to in case the server is down again


the only new things: 1) more complete desc of jtagtools install under cygwin 2) easier way to flash bootloader and new bootloader file




what you need:
- PC with windows (98 or later), or linux works too, but this description applies to windows
- if you are on windows, then also cygwin from http://cygwin.com
- parallel port on PC
- jtag cable, schematics for a working example (very simple!!) here: http://hpcmonex.net/nec900/files/jtag/900c_jtag.jpg
note, this emulates a wiggler cable... you can also order some more serious type of wiggler but that costs more.
- soldering iron and the right screwdriver to disassemble the 900c
- bootloader file http://hpcmonex.net/nec900/files/jtag/bootloader410_nolockcheckmsbin_jtagONLY.zip
- jtag tools 0.5.1, here's a version compiled for cygwin: http://hpcmonex.net/nec900/files/jtag/jtag900cfinal.zip


steps:
1. after you got all the above, disassemble the 900c, hpcnec has a disassembly guide here: http://hpcnec.com/cgi-bin/hpcnec.cgi?fid=15&topic_id=1204570453
2. solder the jtag cable to the jtag pins on the 900c like this: in this picture and sort out the LPT end on the PC too.
NOTE: an alternative jtag header and pinout exists on the motherboard, for more information refer to the hpcfactor thread linked at the bottom of this page.
3. now to make the software work... assuming you are on windows, download and install cygwin from http://cygwin.com. when it gets to ask you about which packages to download,
leave all that on default except for an extra package you need, it's ioperm under Devel packages.
4. using cmd.exe, cmd into cygwin\bin and run this command: ioperm -i
5. after that, here is the already compiled jtag tools for cygwin in windows: jtag900cfinal.zip. download and unzip that to cygwin\home\yourusername\jtag. then copy the jtag folder within usr\local\share from jtag900cfinal.zip into cygwin\usr\local\share\jtag now it's all ready...
to start jtag tools, run cygwin from the cygwin icon on desktop or start menu, and from the cmd it opens, issue this command: cd jtag, then issue this command: cd src, finally issue this: ./jtag
6. connect the 900c if you haven't already, and power it up by simply inserting the battery and putting it on AC power as well! type this command: cable parallel 0x378 WIGGLER
(check if your parallel port is indeed on 0x378, in device manager, lpt port, resources) it should say Initializing ...
of course, if you have a non wiggler cable that is supported by jtag tools then use the name of that instead.
7. then type this command: detect
this should tell you your CPU is a PXA255A0.
if it doesn't return anything, make sure the device is on AC properly / battery is fully charged. the point is that the board must be powered on for detect to work.
8. next command is: detectflash
that should return lots of info on the flash
9. now try reading your current bootloader image (not mandatory): readmem 0x0 0x80000 filename
you can check its contents or compare it to saboot.nb0 bootloader image to see if it is the same... if not then it's probably corrupt and you have a good chance to revive the device.
10. now flash the file you extracted from the bootloader download: flashmem msbin saboot.xip
if verification is ok, then you are almost finished now.
11. disconnect from the PC, remove power from 900c, and try reinserting battery and powering up. it should boot up now! if not then maybe something went wrong, try jtag again. note, it's fine if it doesn't boot to OS, just bootloader. you jtagged bootloader 4.10 in, so feel free to just reflash an OS!



troubleshooting:
1. if you had a 900 running hpc2000 OS then the above posted bootloader will not boot the OS. but the solution is simple: you can choose to keep hpc2000 or upgrade to cenet.
if you want hpc2000, then just download and flash this hpc2000 image compatible with cenet bootloader. if you want ce.net then download stock cenet rom from my download page (select any of the options except "Not listed".
then, flash the image from CF card using C+F method (how to described at this link).
2. if cygwin won't run jtag tools then read more for a solution: 1) extract jtag900cfinal.zip somewhere else on your PC outside cygwin folder. 2) take the cygwindlls folder from the extracted jtag900cfinal.zip and copy the dlls from it into \src folder. 3) then copy the jtag folder within usr\local\share from jtag900cfinal.zip into cygwin\usr\local\share\jtag. 4) then, simply (using windows cmd.exe) cmd into the \src folder where you copied the cygwindlls folder contents too and type the command jtag to run jtag tools. hopefully that works.


Edited by cmonex 2008-04-27 1:34 PM

Cmonex, when I get to point 10 and type the command: flashmem msbin saboot.xip I get error:"unable to open 'saboot.xip'!"

I tried to put the saboot.xip bot in my local drive and in the cygwin folder with the same result..

Thanks



airhook, just noticed your post..thanks

Edited by Dan 2008-07-03 10:13 AM

ok, are you sure the .xip file is in the same folder as jtag program. i.e. the ....\jtag\src folder.

but this means your 900c's are now responding over jtag?!

So far I tried the jtagging process with only 1 of the 2 bricked 900c's and it responded for all the process untill point ten..Even the charge led (which didn't work any more after the 900c had bricked) switched back on during the process!

I'd have tried to put the bootloader into the jtag folder..but, while moving the 900c from 1 desk to an other, 2 of the 5 cables (which had been soldered by a friend of mine) have unsoldered from the motherboard so I really cannot try to bring to process to the end

I'll have to ask my friend to solder the cables again. I'll keep you updated Cmonex.

So the saga continues..




Edited by Dan 2008-07-04 2:28 PM

the led comes back, yes, because the processor is no longer crashed. I don't know why else it would do that

yeah, they can become unsoldered if you are not careful. I'm planning to release this fake CF, really a jtag card, you plug it in the CF socket then you are ready to go. (it needs to be implemented first, don't know when, yet :/ )

If the processor is no longer cashed have I got any chance to get the bootloader to be loaded by the C+F keys? Or does the C+F keys function needs to have the bootloader already installed and only loads os?

Nice idea the Jtagging CF card

Edited by Dan 2008-07-04 4:26 PM

well, it is not crashing... it is in JTAG test mode. there is no code in the flash that it can execute, until you JTAG the bootloader in.

Clear, thanks

So finally 1 of the 2 900's is back to life (as the debugging process took about 40 minutes, I had no time today for the second one ).
Here are two pictures showing the jtag cable connected to the motherboard of the 900 during the jtagging process and the desktop PC monitor during the debugging process.

Thank you very much indeed Cmonex







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DSCF0001.JPG (76KB - 6 downloads)
DSCF0012.JPG (74KB - 7 downloads)

wow! nice pictures too

hehe that 900c looks messy, I usually jtag with the screen back on the device.

but the jtag card will be best. soon

is now the second 900c unbricked too, yeah?



P.S: the bootloader link I put up for the jtagging points to a bootloader patched by me so it doesn't care about the battery lock so when reassembling no worries about that lock.

Edited by cmonex 2008-07-22 5:31 AM

I attempted to do one of these cables today to bring back one of my bricked units, and wondering how critical the diodes are? I didn't have any 1N4148 diodes on hand, so I attempted to use 1N4001 which I have a ton of. But I'm not getting any response at all when I issue the detect command in jtag.

Also, is it possible to get the mating connector to use the jtag header on the motherboard, rather than the pads under the CF slot? I already accidentally pulled up part of the pads, and if these cables come loose again, I may not have anything else to solder to... :/