G50-30 System is unstable after BIOS upgrade

Question

After installing Windows 7 I decided to upgrade BIOS and picked the proposed update for Windows 7 64bit (http://support.lenovo.com/uu/en/products/laptops-and-netbooks/lenovo-g-series-laptops/g50-30-notebook-lenovo). 
After applying the upgrade system boot failed. This issue was fixed using yapha7's advice (see this thread: https://forums.lenovo.com/t5/Lenovo-B-and-G-Series-Notebooks/Lenovo-G50-30-Bios-update-crashed-installed-win-7/m-p/1693051#M32265).
Well, OS boots. But now I can draw violet lines on a viewport by pressing two mouse buttons simultaneously. WLAN breaks periodically, gets fixed by a reconnection. CPU consumption increases without any resorce-intensive task being launched. It iss understood that latter two issues might not be related to a BIOS upgrade. But they all appeared shortly after the upgrade.
Also it is not clear if I'm able to use USB 3.0?
The current BIOS version is A7CN47WW. Is it possible to rollback? Can you provide the original / any stable BIOS version (for Lenovo G50-30 Windows 7 x64) which is prior to the one available at the drivers download page? Thank you!

Answer 1

hi a_demenkov,
Just to check, have you considered reinstalling Win7 after you got the issues that you described after flashing the BIOs to v47?
If you're leaning towards downgrading to the BIOS to v45, try the following:
1. Boot into the BIOs and enable BIOS Back Flash.
    - Sample image
2. The BIOS v45 download link is not listed but if you look at the the BIOS v47 file below, you should be able to get v45 by renaming:
BIOS v47
https://download.lenovo.com/consumer/mobiles/a7cn47ww_64.exe
to
BIOS  v45
https://download.lenovo.com/consumer/mobiles/a7cn45ww_64.exe
If you're not able to flash the BIOS inside Windows then you may need to do it under DOS.
How to flash InsydeH2O EFI under DOS enviroment
Goodluck!