Nexus 5X Résurrection [Bootloop Edition]

anon46267848 · February 23, 2018, 7:33pm

So after two years of service, my dad’s Nexus 5X decided to go into a BLOD (Bootloop of death).
Normally I wouldn’t waste my time fixing cheap hardware, and my dad’s happier with the new iphone I got him anyway, but since this is a Nexus device and I have a soft spot for those, I made an exception and decided to fix it.

So what do we know about BLOD?
-The phone has got a Snapdragon 808 chipset, we know that chipset along with the Snapdragon 810 from Qualcomm is trash.
-The bootloop is caused by an issue with the A57 cores (2x A57 + 4x A53 cluster)

The solution
-Flash a new system image
-Disable the A57 cores

The issue at hand
We need to enable Allow OEM unlocking to get anywhere.
However this can only be enabled within Android, on the phone, in developer mode.
The phone is already stuck in a bootlop with Allow OEM unlocking disabled so if we can’t get the phone to boot, we’re basically f***ed.

Let’s begin.

Step 1
Try to turn on phone = fail, stuck in bootloop
Boot into bootloader = success

From here I can’t do anything with the bootloader locked.

Step 2
Leave device running in bootloop to see if anything changes = fail, surface temperature above the SoC <70 degrees, turn it off before it blows up.
Try to boot with SoC at room temperature = fail, however at the first boot after 90+ minutes powered off the device seems to go a few seconds further into the boot sequence.

Step 3
Open it up and expose the SoC

Now let’s take off the little IHS to find that Snapdragon

Ops! Wrong side, flip and try again!

That’s more like it, the Snapdragon is hiding under that DDR chip.

Step 4
So we know the device is seemingly getting further into the boot sequence when at room temperature, so maybe even colder will make it boot?
Let’s put the motherboard into the freezer to find out.

Leave in freezer for 15 min, quickly remove and inspect for moisture, hurry up and connect the battery and the screen and attempt boot.

Step 5
20 seconds later we’re attempting first boot and * drumroll * it works! (nofuckingway.exe)
Now rush into settings, enable developer mode, Allow OEM unlocking and enable USB debugging.

While doing this I was just holding the screen, motherboard and battery sandwiched together in my hand, trying not to tear any ribbon cables or short anything while operating the device. This was waymore troublesome than it sounds.