Just the GPU card. If the manufacturer of your GPU card has a vBIOS update that would be the safe way to upgrade your vBIOS. But if you modify the current vBIOS and you input a wrong data. Your GPU card may not work correctly or not work at all. You really need to know what you are doing to modify your current vBIOS.
Mostly black screen occurs because of incorrect voltage determined by EVV or faulty VRAM or some power issues.
When you use your graphic card without the driver it stuck at idle clocks so everything is fine, but as soon as you install the driver a memory clock could jump to its max value and system immediately crash with black screen. No matter what windows version is installed.
There are two ways to fix it by modding vbios:
1. set up manual voltage for all DPM states, generally it's possible to do even some downvolting (most reference r9 290 can work at max voltage 1.175-1.200v instead of 1.250-1.275v used in stock vbios)
2. downclock vram
//everything above is actual for r9 290/390, but maybe it's applicable to some other cards (step 2 at least). I never modded vbios for an older than r9 290 cards.
for hawaii and polaris you can easily find good guides on overclock.net by googling "hawaii bios editing" or "polaris bios editing".
for other cards I don't know, guess this one should be useful for tahiti ATI Hd 7950/7970 bios mod thread
I'm having the same problem when installing newer drivers like 17.12.1/2. Black screen during installation (forced to reboot PC manually) and after Windows boot logo only black screen. When I run 17.7.2 however, everything is rock stable.
I'm glad to hear that setting manual voltages for each DPM state helps, modding vBIOS cannot be the solution, if this issue doesn't occur in any driver version. Maybe Wattman is initialized in a wrong way for some cards?
wattman should be disabled by default at clean driver installation as far as i know. You need to accept some agreement on wattman page before it get enabled.
If you are able to install the old driver and use wattman you could try to set up all settings (voltage and lower memory clock by 50-100mhz) in 17.7.2 and then update driver to newer version without uninstalling it. Maybe it will work that way, don't know. I prefer to use the only driver itself without control panel, relive and other software + modded vbios with all settings what I want, so I saw wattman interface only on screenshots