Flashing Stock VW to Stock VW

[jmkizer]

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Just a thought here. For those who wish to take a stock VW software load and simply update it to the latest factory code could their not be a simplified flash procedure? I was thinking is it required to unlock the ECU or could one simply pick Flash Stock (re-lock ECU) and upgrade the factory firmware from one version to another?

[bri3d]

could one simply pick Flash Stock (re-lock ECU) and upgrade the factory firmware from one version to another

Yes, do this and pick an FRF. Make sure that the upgrade has compatible immobilizer data so you don’t make a brick. That’s all there is to it.

On Thu, Jun 5, 2025 at 6:33 PM jmkizer @.***> wrote:

jmkizer created an issue (bri3d/VW_Flash#169) https://github.com/bri3d/VW_Flash/issues/169

Just a thought here. For those who wish to take a stock VW software load and simply update it to the latest factory code could their not be a simplified flash procedure? I was thinking is it required to unlock the ECU or could one simply pick Flash Stock (re-lock ECU) and upgrade the factory firmware from one version to another?

— Reply to this email directly, view it on GitHub https://github.com/bri3d/VW_Flash/issues/169, or unsubscribe https://github.com/notifications/unsubscribe-auth/AABTO2P4PRUZ6FETCKFVFK33CDOWHAVCNFSM6AAAAAB6WZDCIGVHI2DSMVQWIX3LMV43ASLTON2WKOZTGEZDGMJYGY3TOMI . You are receiving this because you are subscribed to this thread.Message ID: @.***>

[jmkizer]

Some thoughts:

1. What would constitute / trigger a lock based on immobilizer data? For example. I am looking to update a US -> US, same ECU HW PN, same ECU SW PN, and one revision up. i..e 3CN906259_0005 to 3CN906259_0006. I couldn't imagine a immobilizer lock based on this.
2. Could we not add a warning in the GUI that would check for an incompatibility in the files that MAY trigger and immobilizer lock? Perhaps the next version? Additionally, we could change the text of the buttons/selection options to make this a clear path of upgrading ECU files without having to unlock.

[bri3d]

3CN906259_0005 to 3CN906259_0006. I couldn't imagine a immobilizer lock based on this.

Right, this will generally be safe.

Could we not add a warning in the GUI that would check for an incompatibility in the files that MAY trigger and immobilizer lock?

This is actually much more difficult than it seems; we would need to either automatically identify the ImoDat section of the calibration and cross-correlate it against some sort of database of other files, or we would need to trust the "allowed box codes for update" section of the ODX, which is frequently too restrictive. Anyway, see below for why I haven't been too keen on this.

Additionally, we could change the text of the buttons/selection options to make this a clear path of upgrading ECU files without having to unlock.

This tool was always intended to be more of a research tool more than a diagnosis and repair or even a tuning tool (although of course tuners are gonna be tuners so they've latched onto it), so I'm not particularly keen on adding broad swaths of functionality for situations that already work fine if you know what you're doing. I'd consider SimosTools to be a "sister project" that's more focused on being user friendly, containing stuff like a list of allowed cross flashes etc.