[Q] Trying to restore Nexus 4, would shutdown when unplugged… seeking help

Hi folks,
Fortunately I've not had much necessity to post here for help. However, that's now change.

I am looking for suggestions on:
1) What might be the cause of an issue with my N4
2) What I might be able to do about it.

Here's the background:

• My N4 was working fine. Stock device, 4.4.2, no rooting, etc.
• The other day it spontaneously turned off. I was not able to turn it back on. "Google" would appear on the screen, but a few seconds later would vanish and device was off again.
• I did figure out I could turn it on (most of the time) when it was plugged into a power source. But detaching from that power source (whilst it was running) would result in it turning off within a couple of seconds at most.
• I managed to back up most of my data, whilst having it plugged in and turned on.
• A few days later device tells me there's a 4.4.3 update. I update it.
• Issue remains.
• I then try to initiate a factory reset.
• Device reboots during that process. But fails to restart.
• I could no longer restart it whether plugged in or not.
• It can sit in bootloader mode without being plugged in, for as long as it takes to run the battery down.
• It can't be in recovery mode without ext power.
• I load the TWRP recovery image. That is on and working fine.
• I can access the device with fastboot command (via Windows 7)... which is how I got the TWRP image on there.
• In recovery mode the device is not detected by windows, and adp command can't see the device.

This is about where I have come unstuck. I was attempting to install a clean Android 4.4.3 image onto the device. But I can't get ADB access to it. Tried on a Mac and a Windows 7 PC.

UPDATE: I did manage to complete instructions for installing new Android 4.4.3 image over fastboot mode. But even after completing the steps successfully, device won't start. Just "Google" flashes up, and devices stops after few seconds.

HARDWARE FAILURE?: It's possible this whole issue is hardware related and I'll have to ditch the device. If that likely? I've seen some people mentioning similar issues, which they resolved by replacing the USB port board. Is that likely to cause this kind of issue?

Does some kind person have any suggestions on steps I can from here?
I'd really like to recover this beast... it's my first and only smart phone, and would hate to drop to a cheap replacement cell phone for the foreseeable future.

Thank you...

Somehow my title was blank (just a [Q]). Might explain why I got no replies so far :silly:
Updated.

lolcakes203 said:

If its happening even after a full reset and flashing of the factory image, that most likely means it is a hardware issue, maybe the battery. You can try changing it yourself or getting someone else to do it. This is what I think the issue is.

Click to expand...

Click to collapse

Hi there,
Thanks.
Regarding the battery... I had considered that. Although the battery was working fine right up to the time the N4 started having issues. Even during the issues... I could charge and discharge the battery as per normal. I tested this by discharging it by leaving the N4 in bootloader mode, and unplugged. After about 12 hours it would discharge completely. I was then able to charge it up, as per normal.

So that had me thinking it was not likely the battery at fault. What are your thoughts?

DrFredPhD said:

It sounds like the battery to me, running in bootloader mode requires nowhere near the current that the full OS does.

Click to expand...

Click to collapse

I apologise for taking so long to respond. I don't seem to be getting notifications. Will check into that.

With regard to the battery... When the phone is fully charged (and it was just like normal... prior to me toasting the OS in an attempt to refresh the device, AND it charges normally by plugging it in when turned off or in BL mode), it takes perhaps 12 hours or more to discharge, with the screen on permanently, whilst I leave it in BL mode. So if the battery is the issue, it's certainly got nothing to do with the battery being able to receive and take a charge. That happens absolutely per normal.

What I am wondering, however, if perhaps the USB board could be faulty? I actually replaced the USB board a month or two ago, as the connector on the original one died and Google refused to repair it on warranty because there was a crack on the back glass. The replacement is an LG part. I am wondering if there might be something in that logic of that board that is screwing up... such that when the cable is unplugged the device somehow "thinks" it is plugged in and thus in charge mode, rather than drawing from the battery. I am not sure where the logic for the device to determine whether to draw current from battery or USB resides. But is it feasible that this might be going on?

I'd love to revive this little brick back to smart-phone status.