I've been on XDA before and I use it all the time when i've rooted stuff and messed around with my phones. I successfully rooted a GS3 last year and it was awesome and this year i have an LG G2 (ATT version D800). I rooted it a few months back and it took me a little while to do it but it worked. I didn't flash any custom roms or anything but i did use Xposed all the time and it was awesome.
Yesterday like a dumbass i took an OTA update and it put my phone into a bootloop with the message:
ERROR: Boot certification verify
Secure booting error!
Cause: Boot certification verify
Now all my phone does is light up with the LG symbol, flash that message, turn off and keep repeating. I have no download mode, I have no recovery, there is nothing I can do with any variations of button holdings and presses. I can turn it off but I have to hold the power button down for like a solid 15+ seconds to get it to stop. I was running stock firmware from LG, never flashed a single custom ROM on this phone (but I am familiar with it since i use to do it with my GS3 all the time).
Idk what to do, i've been all over the internet and XDA trying to fix this and figure it out. The major problem that I have is that I have a macbook and I know everyone uses PC so not everything from XDA applies to me unfortunately. I don't have access to a PC either unfortunately bc otherwise I would just try fixing it with a PC.
I do have ADB and I have just a little knowledge with that but nothing to extensive.
Please please please help me out, i've never posted anything on a forum before so I hope you guys can help.
PS, I did go to the thread http://forum.xda-developers.com/show....php?t=2582142 and that looks great but idk anything about Ubuntu and that whole thing seemed foreign to me unfortunately.