LMM operating system

67Camimo

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Feb 28, 2022
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Hi y'all, I'm new to the forum and am trying to get my feet wet with learning how to tune myself. My truck is already tuned and I'm happy with it but with the EPA being the way it is I want to learn myself so I can troubleshoot any problems and make changes as I need. I never saved the stock file when I flashed the DSP5 tunes but I got a stock one from someone and the OS is 12628594 which is the same as a couple other tunes I've seen on here. However the OS from the tuning currently on my truck is 11720809. Can someone please help explain what the OS is and the significance of it. I've seen people posting their VIN when asking for a stock file asking for the correct OS. My vin is 1GTHK23608F145363. 2008 GMC Sierra CCSB 4x4. Any help would be greatly appreciated.
-Dylan
 

67Camimo

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Feb 28, 2022
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Your dsp5 file changes the os and that’s why it’s different.
So if i wanted to test out the tune I'm making by full flashing it and then go back to my current DSP5 tunes i wouldn't have an issue? I've heard that people get corrupted tunes.
 

darkness

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On the lb7 it can be an issue, I’m not sure of the stability of the lmm. I’m sure someone can confirm or deny it.
 

N2BRK

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Dec 31, 2009
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I'd have to search but I know I posted something here years ago in a thread with Ferm - the 594 is the latest LMM OS and there was an older OS that was prone to eventually causing a no-start condition. Do some searching, but the 594 should be the most up to date OS for an LMM.
 

67Camimo

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Feb 28, 2022
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I'd have to search but I know I posted something here years ago in a thread with Ferm - the 594 is the latest LMM OS and there was an older OS that was prone to eventually causing a no-start condition. Do some searching, but the 594 should be the most up to date OS for an LMM.
Ok that makes a lot of sense. Do you know if switching between tunes with different OS will be a problem? I'd hate to corrupt the tune file i paid for and be stuck with a shitty tune I'm trying to learn with.
 

N2BRK

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I’m pretty sure that you can’t cal flash onto a different OS. You’d have to match the OS. To go back to your tune in the other OS, you’d have to full flash back.
 

N2BRK

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No. Once you full flash to a dsp5 OS, then you can quickly cal flash your changes (as long as you stay with the same OS).
 
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67Camimo

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Feb 28, 2022
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That makes sense. If i have the DSP switch installed and load a single tune will the ECM be confused or run the single tune and basically ignore the switch? Sorry for all the questions I'm not great with computers and this is all brand new to me.
 

2004LB7

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Dec 15, 2010
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you have to full flash for changes to DSP areas but only have to cal flash for the rest of the tune.

to flash a non dsp tune over a dsp you have to full flash. to install a dsp you have to full flash. to install different OS version you have to full flash
 

darkness

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That makes sense. If i have the DSP switch installed and load a single tune will the ECM be confused or run the single tune and basically ignore the switch? Sorry for all the questions I'm not great with computers and this is all brand new to me.
You can leave the switch in place it won’t affect anything.