Modifiy system NAND outside of IOS (yes I am aware of the risks and I do have a BootMii Boot2 backup

My Wii has been having an issue where it boots to a black screen after the health and warning, EXCEPT in maintenance mode. After a few months of trouble shooting I have narrowed down the issue to possibly be the file /title/00000001/00000002/data/cdb.vff. After messing around with the file in dolphin I have found that deleting it will just cause the wii to regenerate it with no loss of save data, installed channels, or Miis. Normally, I would use WiiXplorer HOWEVER, the file seems to be VERY broken. I cannot copy to an sd card, change it's location, rename it, or delete it. Attempting to use WiiXplorer's calculate MD5 hash function causes a giant error exception screen to appear when used on the file. To make sure WiiXplorer was not broken I attempted to copy and paste settings.txt from the same folder to my sd card which worked fine. My next idea is to use a program outside of IOS similar to BootMii to modifiy it, the only problem, I can't find anything that can do that, I can't even find another normal homebrew application that works as a file explorer other than WiiXplorer. I would like to know how I may fix this or a different solution to my problem.

Yes, I do have a BootMii under Boot2 backup of my nand along with PriiLoader. I do NOT have a backup from before the problem,

 

I don't understand how this helps me. Isn't there a homebrew application that can fix mail brick.

I like my games and save data.

 

I don't understand both options, are you suggesting I get a 4.3 U System Menu WAD from NUS Downloader and install it using something like mod mii. What settings do I input into NUS to get the proper wad (patch IOS, keep encrypted / decrypted contents, etc). What do I lose if I reinstall the system menu and can I back it up then restore it after I reinstall?