BIOS Upgrade help

Hello I am considering testing out a different BIOS on my main PC as I have recently been getting some 'BAD_POOL_HEADER' BSOD's in my windows 10 B1803 installation.
I'm currently on BIOS 3.20 & I was wondering if I want to try out 3.50 do I need to go to 3.40 first ? or can I go straight to 3.50 ? also is it possible to go back from 3.50 to 3.20 ?

Specs:
Mobo: Asrock gamingX X370 BIOS 3.20
CPU: Ryzen1600
GPU: GTX 1070
PSU: Seasonic 620w
RAM: 32GB GSkill TridentZ @2800MHz
2 Samsung SSD's 250GB & 500GB

I haven't updated the bios for this in along time so I'm alittle rusty at doing doing this ;)
Thanks

Hi, I don't have this board, but I can tell you that it's really important to follow the instructions on the BIOS downloads page when they tell you "If the current BIOS version is older than ___, please update BIOS to ___ before updating this version." Do not do direct upgrades if they tell you to first upgrade to an intermediate version! It's usually possible to downgrade, but not always ("User will not able to flash previous BIOS once upgrading to this BIOS version." for some of the latest versions).

I've always used instant flash so far. Instructions are here : https://www.asrock.com/support/BIOSIG.asp?cat=BIOS10

My advice is to download the BIOS file twice, and to compute a hash (SHA-256 for example) and check that you get the same thing. By doing so, you make sure that your download wasn't corrupted. You can also check again that the file was copied exactly the same to your USB stick.