change Service Tag on Dell latitude 7490

[vamota]

hi, I'm trying to change the Service Tag on my Dell Latitude 7490 and would appreciate some pointers/links on the best way to do this.

I'm thinking to get the BIOS into Manufacturing mode , from where I can simply type in a new Service Tag. But I've not been able to find how to get it into Manufacturing mode.

I have recently got a T48 programmer which seems to work fine with the Latitude 7490/7400 in-circuit, and I successfully used it with rex98's excellent -8FC8 patcher to remove the system password on a colleague's Latitude 7400 : it appears to work by putting the bios into Manufacturing mode.

I saw a YouTube video which showed that for -8FC8 motherboards you can hex-edit the extracted BIOS file and change a couple of instances of "00 FD AA" and "00 FC AA" to "OO Fx 00" to put it into Manufacturing mode. I tried this on the 7490 but unsurprisingly it didn't work.

So I'm wondering if I can do something similar for the 7490 ( motherboard DAZ40 LA-F322P , which is a -E7A8 type motherboard).

I also had a look in the extracted BIOS file using UEFItool but since I'm a bit of a novice at this it's all a bit unclear : I need to educate myself on what gets stored in the various regions etc - any pointers/links welcome.

Happy to post the BIOS file if that helps.

[LBTT1121]

hi, I'm trying to change the Service Tag on my Dell Latitude 7490 and would appreciate some pointers/links on the best way to do this.

I'm thinking to get the BIOS into Manufacturing mode , from where I can simply type in a new Service Tag. But I've not been able to find how to get it into Manufacturing mode.

I have recently got a T48 programmer which seems to work fine with the Latitude 7490/7400 in-circuit, and I successfully used it with rex98's excellent -8FC8 patcher to remove the system password on a colleague's Latitude 7400 : it appears to work by putting the bios into Manufacturing mode.

I saw a YouTube video which showed that for -8FC8 motherboards you can hex-edit the extracted BIOS file and change a couple of instances of "00 FD AA" and "00 FC AA" to "OO Fx 00" to put it into Manufacturing mode. I tried this on the 7490 but unsurprisingly it didn't work.

So I'm wondering if I can do something similar for the 7490 ( motherboard DAZ40 LA-F322P , which is a -E7A8 type motherboard).

I also had a look in the extracted BIOS file using UEFItool but since I'm a bit of a novice at this it's all a bit unclear : I need to educate myself on what gets stored in the various regions etc - any pointers/links welcome.

Happy to post the BIOS file if that helps.

attach bios original

[vamota]

bios file attached, motherboard DAZ40, LA-F322P. Current service tag : 7XD4HR2 . Desired service tag: 1N9FTT2

[vamota]

P.S. I should add that the reason I want to change the Service tag is that the laptop is enrolled to Microsoft Autopilot, and this is what I want to get rid of : I had assumed that changing the service tag was the best way to do this, but I have just discovered a separate active thread Dell Microsoft autopilot issue on this forum with screenshots outlining how to get rid of Autopilot by editing/invalidating the AUTOPILOT_MARKER sections using a hex Editor. I tried doing this on my bios, but wasn't clear on how exactly to do the invalidation step , so was not yet successful ..