Flashhack – Unable to install recovery rom errors

Q: While using flashhack with my LT1, I get an error about being unable to install the recovery rom on the t-side or e-side.  Why does this happen, and what should I do?

A: With LT1 ecms, by default, we modify some code before writing it to the ECM, and also change the order that the programming is written. This should, in most cases, allow the ECM to remain bootable most of the time if something goes horribly wrong during the flash procedure.  This helps only in rare cases of stupidity like someone turning the key off on your car while programming.  It’s called the recovery rom.

These warnings pop up for you because the area of code we are modifying is not as expected, and since anything could happen if we don’t understand your existing ECM code, we ‘play it safe’ and forbid installation of the recovery rom.

If you get this error, your bin may have code patches installed in it, or may be an uncommon revision from GM.  Modifying a common bin using ordinary tuning procedures should not trigger this error, nor should really common patches such as the ones in EEX.

You can either change to a bin that is unmodified in those areas, or uncheck the option ‘Install recovery rom on …’ in the parameters.  Make sure nobody disconnects power from the ECM until your flash is successful.

Thanks for the beer

I just wanted to write a quick note to all of the users of my software that found a few bucks to send to my beer fund.

I’m not a professional programmer, and through your generosity, I know you all appreciate the ridiculous amount of time I’ve put into writing this oddball code for rare ECMs in a cold, dirty, low-budget basement electronics lab.

Just so you know, this does not just pay for beer, alongside the few google ads we put up here, it also pays most of my web hosting bills so this stuff can be available to everyone.  It also pays for the odd meal out so my wife isn’t too upset about the time I spend on these projects.

As long as you’re all interested, I’ll keep going with this stuff.

Flashhack P66

Flashhack keeps getting better, thanks to everyone that’s helped me test it.

P66 V6 development has been very slow, since I don’t actually have an ECM to test with, but thanks to some back and forth it seems to be working well.  It shares a lot of code with the LT1 flash tool so I’d expect it to be quite reliable.

I have not removed the ‘for bench test only’ warning for the P66 but if you’re brave please ignore it and give it a try, let me know how it goes


My new LT1 flash tool definitely seems ready for everyday use, but does need more widespread testing.  I would be really suprised if we ever see an accidently bricked ECM with this tool and feel it’s the safest 1994-1995 LT1 flash tool ever (…no warranty though)

It has P66 V6 support coming soon too.


EEHack support

I get a lot of comments posted directly to this site asking for support for EEHack.

If you want to get help with EEHack in any way, please join gearhead-efi.com and ask there.  It’s the only way.  I will not answer comments on this site anymore, I just don’t have time due to my other projects.

2020 Development continues…

Due to a generous donation that got me another test ECM, EEHack development continues with a fresh test bench, socketed up ready to go and communicating with the cheapest FTDI device china has to offer (which is really all you need to tune an LT1, you know)

Thank you to Mogielski and all the other supporters that have kept me motivated to keep working on this platform over the years even without having an LT1.

I plan on separating the flash tool from EEHack entirely and making a better one that will support other ECMs as well.

LT1 Ecm(s) wanted

Wanted: Dead, dying, or spare LT1 ecms for eehack development. Please email me (address in EEHack credits) if you have anything laying around…

Small bug in 4.9

The analyzer in 4.9 had a glitch related to the new size of the VE analyzer. 4.9.1 is on the download page and fixes that bug. Thanks to all that reported it