Lenovo g505s: custom bios coreboot or how to disable the integrated video adapter?

Question

Iron

I have a lenovo g505s laptop, I read about a custom coreboot bios, but it's somehow scary to sew it up. never worked with stuff like that.
And the problem is that my model has two video cards: the first is built into the central processor (a10-5750m) and the discrete 8570M. Because There is not enough RAM in a laptop (16 gigabytes), then 1 gigabyte also eats away this video core, when a discrete video card has already 2 gigabytes of its own RAM on board!
In the stock BIOS, you can enable either only the integrated video card, or Dual Graphics, only the discrete one cannot.
Who tried coreboot? Report your experience, please.

Answer 1

16 Gb of RAM is not enough? We live well...

Answer 2

Really there it is impossible to limit the amount of allocated memory?

Answer 3

syxoi
1) Why is it scary to sew up? Buy the cheapest CH341A from ali (supported by the open-source flashrom program) and SOIC8 clothespin to it. You can flash the BIOS without soldering. Before flashing the coreboot you have assembled, you can make a backup of the factory firmware so that if you don’t like something, you can roll back
2) Inside the ./coreboot/src/device/Kconfig file there is a config parameter MULTIPLE_VGA_ADAPTERS . Default is n. (Unfortunately, this option is not available via make menuconfig). Most likely, this parameter affects the support of a discrete video card (you need to delve into the code to understand), so far it is not clear whether it is possible to disable the use of the graphics core built into the processor through the BIOS at all, or in any case it grabs 1 gig at the iron level ... but even if so, it's still good to put coreboot, it's better than a buggy bios from a manufacturer that has scored / does not update for a long time and over time it will only be covered with mold. and coreboot is constantly updated, new features are added and bugs are fixed