[LG V20 ROMs, Kernels, Recoveries, & Other Developm] syndre:
I was trying to figure out the ViPER4Android driver problem everyone seems to be having, and after 3 long days I got mine working again. I flashed version K of Team DevDigitel's ROM to upgrade but also to try and reproduce the problem again, to prove this fix will work. It did, so im happy to share what Ive learned.

Everyone who wants to flash ViPER4xxxx after flashing this ROM needs to stop deleting the /vendor/etc/audio_effects.cof file or renaming it to .bak l.. Although it's true you get an I/O error trying to install the drivers from within the app unless you change that file, you still need the info inside it.

SOLUTION

There needs to be an exact copy of the RONs original '/system/vendor/etc/audio_effects.conf' file put I "/system/etc/audio_effects_vendor.oonf". It's likely you do not have that file in /vendor/etc anymore so you'll have to get from the zip you used to flash the ROM.

This step is way easier done using a PC, especially with adb

Open up the big zip file you used to install TeamDev"s ROM navigate to /vendor/etc ;extract "audio_effects.conf"from that folder and put it someplace safe. Then rename it to "audio_effects_venfor.conf". Last step is to put that renamed file back onto your device, it needs to end up as "/system/etc/audio_effects.conf" with permission set to 644.

You should be able to install the viper drivers now and have it stick after reboot, and (goes without saying) functioning properly, and processing audio both with the DAC on and off!

I highly recommend flashing your flavor of viper again over whatever you had to be sure everything it needs is in place with perms set before you try to toggle the app on. Also, I don't know if it actually does anything, but I like to plug my earbuds in and play audio through them, toggle sac a few times, and unplug them The idea is you're forcing the system to switch through a few different output methods, getting its head on right before you snack it with vipers processing turned on. Make sure you have everything off in the EQ app before booting up the first time and doing that, obviously.

Personally, instead of the regular ViPER4Android app, I prefer and would recommend to every audiophile thea A.R.I.S.E. Sound System's Deuteronomy project. Ive been using it on previous devices Ive owned, and thats what I have on my V20 now. It offers a ton more of everything. Make sure to read carefully how to edit prop that tells the addons pack what to install, beccause the default will only give you the main ARISE app.

I hope this helps a lot of people get their **** back up and running. It works on my V20 100% for sure after only a dirty flash of the rom, moving that conf file out of vendor/etc to system/etc, flashing ARISE then rebooting. If you do those 3 easy steps the drivers will be installed during the flash. so you will never even see the message asing you to install them manually when you first run the app. Have Fun

you would be saving lots of people from a migraine if you didnt put delete("/system/vendor/etc/audio_effects.conf") into your install-script

I am glad to see you not include viper4android anymore, I just uninstall it immediately anyways.

also, just curious, I was actually looking at your AFH page looking for hintx to solving this viper issue and and saw ~5m after you uploaded googlecontactsdialer.zip

Was there a reason you didnt link to the XDA post that you got it from instead of renaming the file, rehosting it, and not giving a mention? I mean, yes its a simple zip that didnt require much effort to find the files apkmirror and test it worked for sure.. but that isnt the issue. Theres only one place you could have gotten that from, it says "made by" when you flash it. I mean, that link is literally an inch away from the thank-you buttion and you didnt bother. wtf

i debated making this post but knowing it would help untold numbers of others it was the right thing to do