Holden or GM T43 Flasher App

[Rapidfire]

So been busy for awhile now and decided to make T43 Tcm Flasher

I think everyone has covered Ecm - Pcm side of things,

Holden T43 App is still in development stage but it works. Wanting to incorp recovery mode. user interrupted cal upload soft brick recovery. and maybe Vin change ?

If there is enough interest ill, release when finished. Read speeds are fast 1.5 minutes full read and 55 sec flash cal, Being conservative. can be pushed little more

Ill remove all Rapid fire Branding from app, put it as community based Github freeware that can be developed into something ? Or code based used for other projects, Not used for commercial profiting

Intended use was for all Gm T43 workflows and other 6L45/6L50/6L80/6L90 controllers

This was made to be compatible for Tuner Pro with correct XDF

# Holden T43

**Created by Rapidfire**
Version **0.1.61** (Windows file version 0.1.61.0)
Documentation checked against current source and saved development evidence: **24 October 2026**.

## Purpose and current status

Holden T43 is a Windows tool for identifying supported GM T43 transmission controllers, reading a complete raw image, exporting calibration data, inspecting BIN files, and performing an experimental, OS-matched calibration-only write with backup and independent readback.

The app now uses one T43 workflow. There is no user-selected VE/VF split: the controller reports its OS and the app selects an installed, validated OS profile. A vehicle name, transmission badge, successful unlock, or OS number alone does not establish compatibility. This is not universal support for every Holden or every 6L45/6L50/6L80/6L90 controller.

The earlier VF unchanged-calibration write was verified on hardware. The new profile catalog and identification controls in 0.1.61 passed offline checks.

[MPC001]

Cool . Looks like work is on the 10+ OS's, any plans to test on the 06-09 OS's/early boot block?

[Rapidfire]

by MPC001 » Sun Oct 25, 2026 12:32 pm
Cool . Looks like work is on the 10+ OS's, any plans to test on the 06-09 OS's/early boot block?

Hey MPC001, I hope your sitting down for this one
This isn't restricted to Gm base, you just need access to Ecm - Pcm so it can work its magic.

Ill elaborate little later on but is was Big help with OBDX GT Pro, helped me to achieve this for Gm stuff

We would need other scan tools for other manufacturers for process to work then software will work out Boot block and two-way communication

[MPC001]

Cool . Yes OBDX Pro GT is a great tool.

[MPC001]

Hey MPC001, I hope your sitting down for this one
This isn't restricted to Gm base, you just need access to Ecm - Pcm so it can work its magic.

That's magic for sure

[Rapidfire]

Update App now supports user cal recovery, Ive been strict on what you need to do, if it happens

added sim under diagnostics just in case, theirs need to test cal in bin file after soft brick

Ive done it doing a write laptop on my lap and jumped out car and oops.

[Rapidfire]

Cool . Looks like work is on the 10+ OS's, any plans to test on the 06-09 OS's/early boot block?

Sorry MPC001 i veered off subject there, short answer is yes as long as its T43 family

if you have a copy of OS, i can add it then send you app, to test read only. if an error you can send me the log and i can modify.
update the app then send back to try again

you just got to send me the logs in the stages the app asks

This is all safety checks before we write CALS

just need OBDX GT PRO if you have one and a car

and for OS i can write an XDF for Tunerpro with plugin to try

[Rapidfire]

OS`s that are Supported and verified so far

[MPC001]

if you have a copy of OS, i can add it then send you app, to test read only. if an error you can send me the log and i can modify.

The early OS's 24239353, 24243170. Will dig up some bins. Am trying to find a T43 with fried solenoids to use as a bench TCM. Not risking the TCM in the car.

[Rapidfire]

if you have a copy of OS, i can add it then send you app, to test read only. if an error you can send me the log and i can modify.

The early OS's 24239353, 24243170. Will dig up some bins. Am trying to find a T43 with fried solenoids to use as a bench TCM. Not risking the TCM in the car.

Sounds good I can then use OS in app and let it do checksums it will tell me if we have right Bootblock,

If it says no id have to walk you though steps off forum.

And yea bench testing TCM would be great if TCM Supports both OS`s.

I use hp tuners to flash Up and down different firmware`s.

This is what T43 App say`s when its reads different car`s but same OS .... - App included lower-memory data in its compatibility fingerprint, and that differed between the cars. The sedan’s read actually finished, but the app then blocked saving because it didn’t match its expected fingerprint.--- this is what im working on next.