Hello, is there any hardware modification to use laptop without Integrated GPU? I don’t want to use Intel HD for some reasons. I don’t care about battery life. I used a laptop with broken battery for 5 years.
Nope 
If you can’t get back in via hard CMOS clear, then you will need CH341A + SOIC8 test clip cable to fix too
Well, sometimes you can still use external display in this scenario, you’ll have to test
This is my warning when passing out a unlock laptop BIOS now, due to this kind of thing being common
*** WARNING - To ANYONE with laptop and unlocked BIOS!!! ***
DO NOT try to enable this graphics card or disable that card, switch cards etc. Otherwise you will end up with no display output (ie black screen) and no way to recover except by blind flash or with flash programmer.
You can change graphics related settings, like changing memory sizes, or core speeds etc, just don’t try to disable one card or change which is main etc.
Additionally, be very careful when trying to undervolt CPU, you can leave BIOS unbootable due to CPU voltage too low (Sometimes even 0.05 is too much)