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dantmnf / LenovoCustomLogo

Customize Lenovo PC boot logo (screen) without bloatware
The Unlicense
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How is the boot logo actually set? #1

Open dryBoneMarrow opened 10 months ago

dryBoneMarrow commented 10 months ago

I try to understand your code to make a similar script for Linux. If I understand correct, the program sets two firmware variables in the nvram, one with the path to the logo and one with the crc to proof that the file is not damaged. Is this the only thing the program does to set the boot logo (except bringing the file in the correct format and other things to catch errors)? And if yes, how does the laptop know what to do with the variables? Or how do you know that those variables change the boot logo? Because I've searched for some time and I haven't found any information / documentation from lenovo resources for this method to change the boot logo. (Btw. I'm talking about the variables "LBLDESP" and "LBLDVC").

dantmnf commented 10 months ago

It is based on Coxxs/LogoDiy, which IMHO is reverse-engineered from Lenovo PC Manager (the China edition of Lenovo Vantage) and calls one if its DLL directly^1.

This project further reverse engineered that DLL to make direct firmware variable modifications.