ECU Status - Bricked? Bad Tactrix Device?

MiikaS · **Joined:** Tue Jun 06, 2017 6:11 pm **Posts:** 215

RDJ-STi wrote:

From what I’ve heard from Dime, this is going to be a bench reflash. Seems easy enough - essentially 5 pins between the ECU and OP2.0. No ECU disassembly or soldering. Seems similar to the karmanauto ECU clone video I watched a while back.

I’m not sure if you saw the log file and ROM I posted but I definitely see the checksum mismatch on the test write but the actual ECU write showed proper checksums and successful write. I’m still at a loss, despite edm definitions, why it would have bricked so hopefully I’ll understand this better at some point. It doesn’t make sense to me the rom would be vastly different by market. Also worth noting the ECUFlash test write executed absent any errors despite the log clearly showing checksum mismatch and the test write reporting success. It seems like it should have given a failed condition on the test write or prompted to compare the loaded ROM.

In any event, it seems like it I can do the pinout connections and use Dime’s software to recover it I’ll be golden and less apprehensive about dealing with “mistakes” in the future.

I see only test write crc mismatchs with modified areas on ROM compare, same as compare before actual write. And as it is clear, if you have modified ROM, it is different than in ECU. Test write is just comm/kernel testing and it wont write anything, it just tests that everything is working and ready for actual write, hense the crc mismatchs.

rimwall · **Joined:** Fri Aug 21, 2020 10:05 am **Posts:** 321

I had a look at the ROM you flashed. It has the Denso CAN bootloader. The advantage of this bootloader is that it is executed before almost all of the Subaru code and well before any table data is accessed. So, if this ROM was flashed successfully, you should be able to use the Denso CAN bootloader to load a kernel and do a reflash all from the comfort of your laptop.

This flash method is not supported by ECUFlash (to my knowledge). I wrote a java application that uses this flash method with a USBtin as the USB to OBD cable. This doesn't work with a Tactrix. You can read more here: https://github.com/rimwall/USBtinSubProg/tree/USBtinSubProg_test

Alternatively, I think @MiikaS has incorporated this flash method into FastECU. @MiikaS can confirm.

MiikaS · **Joined:** Tue Jun 06, 2017 6:11 pm **Posts:** 215

Yes I have CAN bootloader incorporated into the software and OP2 works as well.

Just select vehicle that belongs to 'sti05' flash method and at toolbar change protocol to CAN (beside the 'Select vehicle' -button) and it uses CAN bootloader.

RDJ-STi · **Joined:** Tue Jan 31, 2023 5:48 pm **Posts:** 20

Thank you thank you thank you!!!! That’s the best news I’ve had and will give me something to work with today. Based on the log, it does appear there ECU write was successful - I just haven’t been able to get the Tactrix / ECUFlash to communicate since that write. Assuming I can get the stock ROM back on that should do it. I’ll update once I’ve gone through this process.

MiikaS · **Joined:** Tue Jun 06, 2017 6:11 pm **Posts:** 215

And EcuFlash will not write any block that has matching crc, so it is 99.99% sure that there is still stock bootloaders etc. in ECU unless there has happend some other unexpected thing, like some electrical failure/spiked that can do something strange thing.

rimwall · **Joined:** Fri Aug 21, 2020 10:05 am **Posts:** 321

The Denso CAN bootloader checks for an access request 7 times very soon in the initial boot of the ECU. It also checks for an access request every cycle of the normal operation.

So, first try to access the ECU using Denso CAN method with the ECU already running. If that fails, you need the ECU to do a cold restart (eg: disconnect the battery or disconnect ECU power harness), wait some time for the ECU to lose power, reconnect power and attempt Denso CAN access within milliseconds. Timing is tricky, so might need to try a few times.

Ideally you want the laptop and software to be constantly broadcasting the access request over the CAN network *before* you power the ECU on. MiikaS might be able to confirm if FastECU will work this way, or requires a coding change.

MiikaS · **Joined:** Tue Jun 06, 2017 6:11 pm **Posts:** 215

It will require code change to constantly broadcast access request, I can do it tomorrow.

lexluthor · **Joined:** Wed May 28, 2025 1:55 am **Posts:** 11

I'm in the exact same situation. How did it end? Did you restore the stock ECU? I bought all the components to try bench flashing it with the OhNineSTI guide on GitHub. But if I can avoid that, it would be awesome.

RDJ-STi · **Joined:** Tue Jan 31, 2023 5:48 pm **Posts:** 20

lexluthor wrote:

I'm in the exact same situation. How did it end? Did you restore the stock ECU? I bought all the components to try bench flashing it with the OhNineSTI guide on GitHub. But if I can avoid that, it would be awesome.

It’s been a while but if I remember correctly I had to remove the ECU and bench flash it back to the stock ROM. Initially it was bricked so I was able to get remote help to unbrick it. I had to be in bench flash for that as well.

It’s not that terrible to remove the ECU for bench flashing and obviously gets easier the more you do it.

Good luck and I hope it goes smoothly.

lexluthor · **Joined:** Wed May 28, 2025 1:55 am **Posts:** 11

RDJ-STi wrote:

lexluthor wrote:

I'm in the exact same situation. How did it end? Did you restore the stock ECU? I bought all the components to try bench flashing it with the OhNineSTI guide on GitHub. But if I can avoid that, it would be awesome.

It’s been a while but if I remember correctly I had to remove the ECU and bench flash it back to the stock ROM. Initially it was bricked so I was able to get remote help to unbrick it. I had to be in bench flash for that as well.

It’s not that terrible to remove the ECU for bench flashing and obviously gets easier the more you do it.

Good luck and I hope it goes smoothly.

I finished all the wiring as the guide. Everything worked perfectly, just added a couple of 12v pins to power the ECU and an additional ground pin. I had some issues with the MAP sensor wiring, I will work on that later.

RomRaider

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