ASUS Flip C100P eMMC install

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ASUS Flip C100P eMMC install

Postby psychoacoustic » Tue Oct 22, 2019 8:47 pm

Hello, this is effectively a repost of a topic I (mistakenly) posted on Software/ARMv7h a few days ago https://archlinuxarm.org/forum/viewtopic.php?f=60&t=14068.

Long story short, I'm trying to install Arch on the internal eMMC of my C100P (4Gb). It works nicely off SD card, but then trying to install onto the eMMC results in the laptop complaining about not finding ChromeOS.

Major problem observed when installing: I get errors writing to the first few blocks of the eMMC. This could be caused by the flash chip failing or the firmware blocking access. For reference, I attached a screenshot of what happens when I dd the backup of ChromeOS back onto the eMMC (which works fine BTW).

So, has anyone managed to get Arch onto the eMMC of the Flip? Or any other Veyron based Chrome device (I noticed the discussion about the Chromebit before https://archlinuxarm.org/forum/viewtopic.php?f=44&t=11232)?

Would flashing Libreboot help? While prebuilt images for the C201P (speedy) exist, I have not been able to build the C100P version (minnie) which apparently are different enough to matter. I don't want to brick my device, since reflashing the chip with hardware is such a pain, even assuming I can do that with a Rpi...

How about with Uboot in flash https://lists.denx.de/pipermail/u-boot/2016-November/272511.html? Anyone managed booting Arch with that?

Thanks for any tips!
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Re: ASUS Flip C100P eMMC install

Postby summers » Wed Oct 23, 2019 9:20 am

I'd try some of the the mdt-tools commands and see what you get ... it will say more than dd can.

Think I've also seen that when the kernel is trying to dive the chip too fast, in which case down clocking can help. That can be done by a device tree modification.

Also look at dmesg, and see if there were any mmc reports during boot.

Actually reflecting on it, I'm not sure if eMMC uses any of the MDT infrastructure. Think when its presented to the operating system its already a proper file system, so mtd not needed. So says best to look at the boot messages and see if there are any clues.
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Re: ASUS Flip C100P eMMC install

Postby psychoacoustic » Wed Oct 23, 2019 8:03 pm

Thanks for the info; I have no idea what mdt-tools are (couldn't find anything thus named in the Arch repos) and I assume you don't mean the Microsoft Deployment Toolkit :lol:

Dmesg didn't reveal any weirdness.

Poking around ChromeOS though I may have found the problem, revealed by the command "mmc": by typing
$this->bbcode_second_pass_code('', 'sudo mmc blockprotect read /dev/mmcblk <n>')
I get
$this->bbcode_second_pass_code('', 'Sector <n> write protection: PERMANENT')
for any n from 0 to 16383, and "NONE" for any above that. I'll try clearing that if it is possible - if that is truly permanent, I'm afraid, it's a lost cause... (without changing the flash contents anyways)

EDIT: Darn, PERMANENT really is PERMANENT...
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Re: ASUS Flip C100P eMMC install

Postby summers » Thu Oct 24, 2019 12:35 pm

mtd-utils http://www.linux-mtd.infradead.org/ its the tools for writing to raw flash.

mmc is flash, but its hidden behind some electronics that makes it look like a normal block device. Usually this works like a normal hard disk device, and so doesn't cause problems.

"mmc" command think I've head of before, but I never used it before, so am not familiar with the syntax, or what the results mean. To my mind though that it can't be written, this for eMMC would usually be through hardware such that one can't provide the electrical signal needed to rewrite the flash. This is where things like the "screw" come in ...

Problem is you are getting into the depths of ChromeOS and the ASUS Flip C100P, Means you'll probably find people with more experience on other forums aimed at exactly this hardware, and Chrome OS.

Sorry this isn't helpful, but best I can you, you have reached the limit of my knowledge. Next thing I'd do though is find the documentation for the "mmc" command, and read it very carefully ...
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Re: ASUS Flip C100P eMMC install

Postby nathan2423 » Tue Nov 12, 2019 11:04 pm

psychoacoustic did you make any progress?

I would like to do exactly the same thing you are doing, or else install debian or ANY linux directly to the eemc. I am finding that running from the card just doesn't work well enough and i want to install to the native drive but don't want to brick this.

Did you find any help anywhere?
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Re: ASUS Flip C100P eMMC install

Postby jewelein » Sat Nov 16, 2019 1:25 pm

Guess the question is can you access all the eMMC in RW mode? many of these machines have a "screw" that needs to be loosened, this opens a contact, which enables mywegmansconnect.com the write to the eMMC. Let me find a link:
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Re: ASUS Flip C100P eMMC install

Postby psychoacoustic » Wed Dec 04, 2019 10:22 pm

Hi all, quick update: The first couple of blocks are write-protected. Apparently the ability to be permanently locked in read-only on a block level is a feature of Flash chips, and I guess ChromeOS did burn that fuse at some point. Luckily, the gpt table appears to be corrupt and it'll simply look at the secondary one. I guess without replacing the chips, that's just a lost cause, and replacing those chips is not economical (with my skills).

However, while looking around about flashing the coreboot I came across this reddit thread: https://www.reddit.com/r/chromeos/comme ... ebook_flip

I'll be playing around with that. I'm trying 0x0d first (FORCE_DEV_SWITCH_ON, ENABLE_ALTERNATE_OS, and DEV_SCREEN_SHORT_DELAY. The first one BTW disables the space bar at bootup, risking loosing the dev mode and wiping the device...) but I haven't tried putting arch on the internal memory yet.
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Re: ASUS Flip C100P eMMC install

Postby BIG666 » Mon Dec 09, 2019 12:13 am

Sorry for the little offtop, guys.
But don't you have Arch freezing when booting C100/C201, as in the neighboring topic viewtopic.php?f=44&t=13913?
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