there's nothing linear about sound levels anywhere, once you've implemented a non-uniform hole in a sack of meat with a meat flap connected to a series of nerves as your mic
there's nothing linear about sound levels anywhere, once you've implemented a non-uniform hole in a sack of meat with a meat flap connected to a series of nerves as your mic
well, i'm stuck for now. the kernel works, reset works, read works, the write routine transfers and executes, but the VPP code itself crashes the ECM and doesn't reach the reply subroutine even though it seems like its identical to the 68K code i was using with eehack.... this might take some time to debug. once that's done i will work on a bit of an interface to load/save bins and let you all play with it.
we're winning!
it reads and writes.
the new logic for handling unknown kernel state on program reboot works perfectly, i made some major mistakes in the flash logic itself, and when i had to quit and recompile flash hack a bunch of times, as long as i didn't cut ECM power, i could re-erase and start over. the eehack bugs regarding re-erase are gone.
it does reboot nicely which means at the very least kur4o's patch goes back to normal execution when we set 'the switch'.
now to test kur4o's patch properly and see if it does hardware recovery on ecm power failure. i'll just yank the plug halfway through and see what happens.
the first attempt to do a hard power fail recovery was no good. i've been in touch with kur4o and we'll figure out what happened and try again
things are going very well with testing. it recovers from all manner of crazy serial noise or whatever. the aldl bus is hard to manage during failure as you can have an arbitrary number of bytes dumped into your 'serial echo', thereby extending it..
i have it in a state where unplugging the serial cable and plugging it back in at random seems to resume okay, and killing the program during a flash is also okay. i even killed it in the middle of an erase and started the program again, and it's good to go.
if it times out from being unplugged too long, you can just press 'flash write' again and it'll start over. if another bus master device takes over, it'll kill that too. it's getting really hard to brick.
there's no recovery from ECM power failure yet but i think we'll get there, as all the technology is there (it uses write block maps, so we can prioritize certain blocks) i just don't think i quite understand how to use the method kur4o came up with yet, and it's probably me.
I haven't followed along with the LT1 stuff as well as I should have. I don't have one of those vehicles to play with. I do, however, have at least 2 bricked pcm's. I was at a dyno shop a few years ago and a guy bricked a couple during flash and ended up giving them to me. I'll have to look if they are obd1 or 2. I'm not even sure these have the gm service stickers on them to identify. Are these recoverable without a hardware attack?
-Carl
In-Tech: If they bricked already and sat on a shelf, you need to directly flash the EEPROM on it with an appropriately-created BIN pair (not the one you flash to a live PCM over ALDL). This would indeed require a direct hardware interface.
Steveo, this sounds amazing!! I can’t wait to test it out on my pesky ‘94. The issue there has never been PCM power loss, so while making an unbrickable routine is still absolutely fantastic, it already sounds like you’ve come up with a sufficiently reliable routine for the issues one of my cars has. Best of luck as always!
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
it's not hard to socket them. i did another other one last night.
you need some thin solder, and some flux.
put some tinfoil around the chip as a heat shield so you only melt the chip itself. you heat gun the old chip while pulling up on it gently, and it pops off. i carefully used a pen torch instead of a heat gun last night and it was okay. then clean up the goop on the board with a pick or something. i use some goop remover with a q tip.
quickly flux and re-flow the solder on each pad on the board and inspect them to make sure nothing is broken from the chip removal. you shouldn't need to add new solder here unless you've pulled part of a trace up (which would be bad)
break the center out of the socket. flux the pins on the socket, melt the flux with your torch, and tin each one carefully with some solder you've pre-melted on the gun.
then hold the socket in place and just touch each pin with your soldering gun.
after you're done you can do a continuity test from the socket to a test point for each pin (the traces are pretty clear)
sounds harder than it is. shouldn't take more than 5-10 minutes even for someone not good at soldering
the chips aren't the cheapest as you need new-old-stock, but if you're careful you can salvage the old chips and use them in the socket.
Hi Steve, Thanks very much for the reply. I've done flash replacement on the 0411 type pcm's. I've got hot air stations and plenty of programming and soldering equipment, can even do some BGA stuff. I don't have the LT1 boxes in front of me to gander at. I am sure this has been covered on this site so a link would be very much appreciated regarding info on what flash chip these use so I can order sockets and maybe some flash to have around. I hate having paperweights, lol
-Carl
The chips are intel an28f512 -120ns, the sockets are pllc32.
The stock chips are very robust so you can reuse them.
You will need to convert the bin to raw format and than burn it. There are some address line swapped.
Why not try to hot swap them, once the flash routine is loaded you will be able to unbrick them on board. There is also some header left that have most of the flash chip pins. Wring the header and adding vpp to the board will be really cool experiments we are trying to do for a long time.[Recovering without removing the chip.]
Hi kur4o,
I'm glad to do some experimenting with you guys. I'm going to order some flash(Is it same for obd2 too?) and sockets in a few minutes for future but we can play with on-board till all the smoke comes out. I'll keep a smoke vac handy so I can put it back in
-Carl
after flashhack has stabilized i do plan to catch this spare ECM on fire attempting to do it.There is also some header left that have most of the flash chip pins. Wring the header and adding vpp to the board will be really cool experiments we are trying to do for a long time.[Recovering without removing the chip.
i do think its possible, because the tunercat/winflash guy has offered a very cheap repair service, and someone i know used it, opened the ECM, and found the chips untouched, so he must have built some hardware to do it...? (either that or traded a core, but i doubt it)
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