Booting the Acer C720 with Fedora 20 Live

Finally was able to boot the Acer C720-2802 with the Fedora 20 Live iso (from a usb stick). At least one hardware issue won’t be resolved until I commit to replacing ChromeOS on the box.

Basically the only thing I’ve found that doesn’t work is the touchpad.

OK, that’s not a trivial thing, at least to me. But there is a fix for it (a kernel patch found in Bug 1045821). This is new hardware, after all, and there was bound to be at least one hardware component whose driver isn’t yet in the stock kernel.

Unlike every other Live image I tried, Fedora 20 consistently reported a “Not enough memory to load specified image” error on first boot and then dropped to a boot prompt. To get around this I had to enter the default image name and set the “mem” parameter to 1980M.

boot: linux0 mem=1980M

Note that using a value over 1980M (for example 1984M) resulted in a kernel panic (my C720 only comes with 2G RAM).

The steps I took to ready the C720 for this experiment:

A. Enable Developer Mode
1. Hit ESC + F3 (Reload key) + Power.
2. CNTRL + D, Confirm. Wait for reboot.
3. CNTRL + D.

All existing data will be wiped as this process invokes system recovery.

Do NOT hit spacebar, it will return the system to factory settings.

B. Enable USB boot and SeaBIOS (Legacy BIOS)
1. CNTRL + ALT + t to invoke crosh window.
2. At prompt type “shell bash”.
3. Then type “sudo bash”.

You are now “root” on the system.

4. Issue this command to enable USB booting and legacy BIOS.

crossystem dev_boot_usb=1 dev_boot_legacy=1

Power off and insert a bootable USB stick into one of the USB ports (I usually use the one on the same side as the power connector, as this is USB3). Then start by pressing the power button and then hitting CNTRL + l (that’s a lowercase “L”) to enter SeaBIOS. Once the BIOS loads the system should read and boot from the USB stick.

SeaBIOS can be set as the default on the C720 by removing the “write-protect screw” and then invoking the command “ 0x489”. Write-protect screw? That’s a hardware thing. The Acer C720 Chromebook page on the Chromium Project site has detailed information on the C720 hardware including high resolution images of the motherboard that indicate exactly where the write-protect screw is located.

I’m not quite ready to pull the trigger on that, although it’s possible I might this weekend. Stay tuned for more.

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About phil

My name is Phil Lembo. In my day job I’m an enterprise IT architect for a leading distribution and services company. The rest of my time I try to maintain a semi-normal family life in the suburbs of Raleigh, NC. E-mail me at philipATlembobrothersDOTcom. The opinions expressed here are entirely my own and not those of my employers, past, present or future (except where I quote others, who will need to accept responsibility for their own rants).