CoreBoot T420 Problem - Sucess flash and boot , but afeter some reboots stop working.

[tailsko]

Hi, I'm new to this community. I tried to install Coreboot on my ThinkPad T420 so I could upgrade to an Ivy Bridge i7.

I read about the process, followed guides, and watched some videos on how to do this. I used a Linux Mint distro with a CH341A programmer connected to my PC to flash Coreboot. I soldered some wires to the chip and, following the guides with a lot of work, built a Coreboot image with SeaBIOS myself.

My PC booted normally, and I installed Arch Linux on it. After using it for a while, I discovered a bug: when I put my notebook into sleep mode, it wouldn’t wake up, only displaying a black screen. I had to force a manual reboot by pressing the power button.

After some time, the laptop stopped turning on entirely. When I pressed the power button, the green light turned on for 1 second and then turned off. I tried removing the battery, clearing the CMOS by pressing the power button, and removing the RAM, but there was still no success.

I reflashed Coreboot, and the laptop turned on again, but with the same sleep mode bug. After some use and reboots, it stopped turning on again, and the green light problem occurred. I reflashed the BIOS 4 or 5 more times, changing some settings, trying Tianocore, and removing some payloads, but the sleep mode issue persisted. Eventually, the laptop stopped turning on again.

I don’t know what else to try. I’m not sure if it's a hardware failure because the laptop still boots and works normally after a new flash, except for the sleep mode bug. I’m wondering if I might have installed the screws incorrectly :p, which could affect booting, or if I might have damaged a capacitor (I know this might not make much sense, but I’m a bit desperate xD).

[independent]

It's been awhile.. I've done a few coreboot installations. One thing that I found, coreboot is not as straightforward a project as laid out on places like reddit. I found a few things not mentioned.

Firstly, this is often pointed out, but memory choice or being picky with memory is a thing. If you have several modules, maybe test with one stick. If it does funky business then try the other. This may happening with memtest86 showing the all clear.

Ivy bridge in Sandy is a bit funny from memory. I did some bizarre memory tricks. Not loading the first 64 bytes or something like that. Also, that it was an error that came up when coming out of S3.

I think I had issues with the latest version at the time. Try another version to compile. That fixed my biggest issues IIRC. Downgrading from 4.20 or 4.19 I think..

People like to post on forums and say everything is awesome, reddit even has a type of post where people just show their thinkpads? Obviously, when things go wrong is where it's most helpful to the enthusiast.

[axur-delmeria]

The fact that there a posts on the Thinkpad subreddit asking for help on how to return to the stock BIOS says that Coreboot is not all sunshine and roses.

I took an interest on Coreboot years back, and did some research. One part I found very risky was the procedure to backup the existing BIOS:

* read the flash chip thrice, saving each to a different file

* perform a bitwise compare between the three files

* if the three are identical, then the BIOS was read correctly <--- That's a very big assumption, one that unfortunately doesn't stand up to scrutiny.
Without a way to programmatically verify/validate the BIOS image, you can never be sure that you backed it up properly.
In fact, it already happened before: there was a Reddit post describing how he bricked his Thinkpad after flashing the backup image he had made using the aforementioned procedure.

Personally, I'd only try Coreboot on machines where replacing the BIOS chip doesn't require a soldering iron.

[independent]

Well, it is kind of esoteric, but well worth the trouble.

I've always made two copies of the outgoing BIOS. Check them against each other then delete one and make an MD5sum of the remaining.

I've reflashed back bioses with a programmer. WSOP chips are a nightmare. SOIC8 chips are sweet. You need a good programmer (not necessarily an expensive one) and a good clip. But once you have that, flashing back has never been a problem. If going back from coreboot to standard BIOS you can do anything just with flashrom as a unified chip from within a Linux. It's getting coreboot on the chips (often split over two separate chips) that's more difficult.

Our friend in Brazil has coreboot on there. They just need to fine tune it a bit. Having a quad core IVY with the cool keyboard is pretty nice.