[G2 Original Android Development] TheUnladenSwallow:
EDIT: Disregard this post, most of it's no longer needed b/c of new bumped bootstacks which I was unaware of XD

[MENTION=3376095]MikeCriggs[/MENTION] I could be wrong but isn't flashing the kitkat modem irrelevant when you flash the lollipop bootstack with the lollipop modem right afterwards? Also the d803 is excluded since it doesn't have a lollipop bootstack, but wouldn't d803 users need to flash the full kitkat bootstack in case they're coming from a 12b base versus just the modem and bootloader? Plus it'd be one less step. (Take all this with a grain of salt, I'm not a dev!)

Edit: Ok, I think I've got this all figured out, but seriously wait for this to be verified before taking my word at face value. So first off the lg devs bootstacks linked in the OP break download mode (at least on vs980), those zips include a jelly bean aboot as well as AN laf partition, but it's clearly not the correct jelly bean laf partition (or at least not on vs980) so I'd imagine it's the default lollipop laf partition, you'll notice that download mode throws a secure boot error and the screen goes black while still being on if you try it (I'd appreciate other variants verifying this isn't a vs980 specific problem, though note that once you flash the kitkat bootloader the test is guaranteed to fail unless for some odd reason they included a kitkat laf partition in the zip, so you'd need to flash the bootstack, STOP, test download mode, THEN go back into recovery and flash the bootloader, ROM etc).

Next up I've verified on my vs980 (and likely everything else other than d803) that the kitkat modem is irrelevant, as I couldn't find a simple kitkat bootloader ZIP I used a different bootstack (we'll talk about that in a second) which is the full lollipop (39a) set of partitions other than a kitkat (28a) aboot partition (bootloader) and laf partition (download mode). I'm also pretty sure that the flash order in the OP will not work.

(This is for anything other than d803) If the kitkat modem and bootloader are flashed and the lg devs bootstack is flashed next then both the kitkat modem AND the bootloader will be overwritten, the kitkat modem is irrelevant and didn't need to be flashed in the first place but the bootloader IS important, so the correct flash orders would be:

NOT D803

LG Devs bootstack

Kitkat bootloader

Rom Gapps etc.

D803

Kitkat Bootstack (WITH KITKAT BOOTLOADER)

Rom Gapps etc.

However there is one final issue with this method, if I'm correct every model other than the d803 would still have a broken download mode if this method was followed, plus I haven't seen a great repository of kitkat bootloaders for people to use and I definitely haven't seen a good repository of singular laf partitions to fix the download modes. For vs980 xdabbeb's 39a bootstack works (this is the one I used and mentioned earlier), the only issue with it being it flashes a one version outdated copy of blastgator's twrp (for now anyways, he usually updates them with the newer twrp pretty quick), so you'd need to flash on vs980:

VS980 ONLY

1. xdabbeb's 39a bootstack https://www.androidfilehost.com/?fid=23991606952613431

2. blastagator's latest TWRP (vs980 version obviously) http://blastagator.ddns.net/twrp/2-8-7-1.php (semi-optional, latest twrp is recommended though not EXPLICITLY required)

*Reboot to recovery from twrp to load up the new twrp version

3. Rom Gapps etc.

OK, that was a long ass post, I don't think I made any mistakes but PLEASE tell me IMMEDIATELY if I did. Hope this helps!