What ROM/kernel combo were you using when it crashed? Also, the new Genysis needs the 20c bootloader and radio so that could be why you're bootlooping?

 

If you can still get to recovery, you should be able to connect the phone to the PC and copy the zips over.

 

Fascinating...

 

And annoying.

What happens if you try another AOSP/CM ROM? Blisspop or AICP for example?

 

All I can think of is your phone is goosed and it's not a software issue.

Does LGUP use download mode to flash? (I presume so)

 

Well, that's interesting.

Guess what's just happened to me? Same ROM, same build.....

Thankfully, a battery pull sorted me.

Googling brings up a few hits, a couple from AF too: http://androidforums.com/threads/kernel-crash-at-boot-no-download-mode.887633/

@iowabowtech the fix you posted there, reckon it'd work for the G4 too?

 

I think they've long since killed bulk mode @El Presidente. So that's likely out. Very strange that a stock rom won't boot unless there's some other smoke and mirrors going on with the CM flash that's also changing other partitions for example for compatibility purposes. I'm not sure what to suggest on that honestly as I haven't followed the nuances of the G4 very closely.

The kdz might be failing because in some cases, a custom rom will replace it's name into the device name field causing the the firmware flashing tools to fail. If you happen to have a tot for this device, you'd likely have more luck as there's some workarounds that can be had using LG Flash Tools instead.

That said, with root and custom recovery, there's a fix there. I'm just not sure yet what to suggest for the safest restore effort.

 

Did you update bootloader and modem with a flashable zip or other method? Just trying to discern what exactly you have right now. I can try to look into compatibility issues if you don't uncover any such info.

And yeah if you can't stay in download mode, the tot won't help in this case. Almost think this has to be a case of needing a matching bootstack and perhaps you have something out of order on that.

 

Googymax is for stock based ROMS I think, no harm in giving it a go at the moment.

I just noticed the 2nd post here

Based on what IBT posted above, is there anything in the "cust" folder that could be tricking the phone in to thinking the software version/bootstack isn't what it is? You should be able to navigate the files on your device from twrp.

Also, there are 20D Flashable zips available now, if you want to try those?

http://forum.xda-developers.com/g4/development/stock-h815-20d-images-kdz-flashable-t3301366

 

Man, it's tough to find a stock rom for this thing. But near the bottom of the RR thread's OP, there appear to be stock roms for V20A and V20B. Have you tried either of those? If not, that would be my recommendation. Just to make sure those were TWRP flashable zips and not firmware packages, I downloaded and checked it out. You can see the contents of the 20B zip, noting the presence of the updater script:

http://imgur.com/Lu33cCc

That appears to contain everything to get to a fully stock setup. Basically akin to a kdz via custom recovery, if you will.

 

Forgive me if I haven't caught up yet but I'm not seeing where you've linked the stock rom I'm talking about. I see that you flashed a stock rooted setup back in post 9 using THESE instructs and files. I'm not recommending that. Instead, the stock rom at the end of the original post in the RR thread link to larger, complete 20B rom. Note the size differences. The one from the tutorial you linked is 832 MB. That is just the rom itself, changing system basically. The full stock rom for 20B is 1.4 GB in size because it contains not only the rom but also the full bootstack and system.

It appears you'd lose root with this method however as su is not included in that rom. But since stock recovery was left out of the zip (see again the screenshot in my most recent post of zip contents), you should keep TWRP and since you have an unlocked bootloader at the moment, you should be able to get root back. I assume this is the intention of that zip being posted there especially since it's flashable in custom recovery but if you or anyone else has reason to disagree, please do.

 

Yeah, the only thing that makes me slightly nervous is that the zip flashes the bootloader and I don't know which bootloader it's flashing though I assume it's 20B as advertised. So with that being said, with your currently unlocked bootloader and TWRP as your recovery...will that cause any sort of upset? Will the bootloader get relocked? And if so, it may not like that considering you have a custom recovery installed which typically isn't a legit action with a locked bootloader. Whoever made this zip may have taken all that into account, I'm just not sure having not been close to the dev community on this device.

So if you want to be super safe, ask around the G4 community and make sure this is a legit way to update an already rooted and unlocked G4 such as your own. I don't want to be the cause of your ending up in a QDLoader 9008 situation, which there's currently not a fix for on the G4 last time I checked.