Solution to hangs on Acer E3-112 and other laptops with BayTrail CPUs

A few months ago I bought an Acer Aspire E3-112 laptop at bargain price, with a "little" problem ...

The seller stated that Windows 10 was randomly crashing even after many reinstalls, and he was unable to pinpoint why, so it might be a bad motherboard. I bought it mainly "for parts", but something caught my attention: AFAK, it seemed to work normally... At least in the BIOS and with a Slitaz Linux live-ISO that I usually boot for testing purposes.

The solution to the problem? seemingly easy, but a little more technical than it seems.

Hang ups, hang ups everywhere

When installing Windows 10, the laptop hung during or at the beginning of the installation. Only once did I manage to install W10, but the crashes were too many. There was no defined pattern and it didn't seem to depend on T °, ​​RAM or mainboard failure. To rule out any specific Windows problems, I downloaded Linux Mint and was able to install it without problems, but on the 2nd reboot (after updating the kernel and various packages) it just hung up as soon as X started.

Searching the internet I realized these crashes are a common problem in almost all laptops/tablets with Intel CPUs of the Bay Trail family, both in Windows and Linux.

The technical details are too much to cover here. These are the links with the most relevant information in this regard:

In short, nobody comes up with a concrete solution. The only thing I get clean is that these CPUs have a bug in the C-States so that when they enter C6, they hang. Even Intel itself recognizes this on VLP52 errata documentation (there was a PDF there but it was since deleted, so I linked directly to the post). Some users succeeded in applying a patch that prevents the CPU from going into C6, but this only avoids the problem and does not fix it.

Tired of spinning around without getting to anything, I made a list of everything I had & hadn't done so far, and realized something. In all cases, I always used the BIOS compatibility mode of the UEFI firmware and never native mode.

UEFI = The unwanted Troll

Many people tend to frown on UEFI when reinstalling an OS, and disable it for various reasons. In my case, since I did not have the original factory/recovery OS (laptop came without HDD), it tought Windows was unlikely to work well, especially regarding the product key. Basically, I was wrong all along.

With little faith and nothing to lose, I set out to make preparations to install Windows in UEFI mode, which were:

  1. Make the respective change in BIOS to use native UEFI mode
  2. Prepare a W10 USB bootable with Rufus, in GPT mode
  3. Install in this way and cross fingers to make it go well

To my surprise, the installation was perfect on 1st try, even recognizing and activating the product key without problems (which surprised me for good). And not only that: I have been using this installation of Windows for more than 5 months without a single hang! How is that possible?

Never before I had such a hard time installing W10 or Linux in BIOS mode on other laptops (HPs are a bitch, but still they do work) and it's the first time I've encountered one that just don't wanna. Which I find serious because it greatly limits the potential use I can get from it.

The only explanation I have is a badly coded, buggy and/or incomplete UEFI firmware. In short, the "solution" to hangs on laptops with Bay Trail CPU is to install the OS in native UEFI mode, since apparently the C6 bug occurs only in BIOS compatibility mode.

As for why it happens, trust me I dont wanna dwelve any more farther than this... If you have a Bay Trail laptop with the same problem, try installing your OS this way. And if it works, let me know in the comments below :)

bios, UEFI, Acer, E3 112, Bay Trail, bug, VLP52