How can I downgrade under Asus Laptop Bios Version?

So since there's a problem with Asus laptop that the onboard sound card and Bluetooth are no longer recognized, we assume that it is because of Bios. Because it doesn't work under Windows 10, because we even tried Android on a laptop where the onboard sound card and Bluetooth are also not recognized.

So we tried to downgrade the BIOS version by downloading Asus Easy Flash. We have downloaded the older version of the bios, but the problem is the software does not allow you to downgrade the version. Because then it says that the version is too old. We tried to downgrade it directly in the BIOS, and it doesn't work there either, because even Bios doesn't allow you to downgrade to a version, but only to upgrade.

Is there still a possibility how to downgrade the BIOS version? Because the Asus laptop is from model L555F

BIOS downgrades are often not possible at all.
That doesn't solve any problems either, but rather creates new ones.
Especially if built-in hardware is not supported in older versions.

Just because the sound card doesn't work on Android doesn't rule out Win10 as a source of problems. I'm guessing missing or incompatible drivers or the usual ASUS nonsense with the "Nahimic service"