Unbricking a Samsung Series 5 550 Chromebook

I recently tried to enable hardware VT extensions on my Chromebook using the Hacking VMX Support¬†instructions on the ChromiumOS website and it didn’t work. Not only did it not work, I also had a second go at doing it, following the instructions verbatim (despite it leaving 3 “bad” instructions in there). This left me with an expensive paper-weight. This is how I’ve come to know how to unbrick the 550.

If you are here I’m assuming you are in a similar situation, and, hopefully, have a copy of the original firmware to hand, with which to unbrick. You will also need another laptop with a suitable Linux distro loaded, such as Ubuntu/Fedora, and have Flashrom installed. Onto parts. You will need a Bus Pirate, a Bus Pirate probe cable, and a Pomona 5250 8 pin SOIC clip. Don’t buy a 3M SOIC clip, the spring is far too strong, and it’s designed in such a way that the pins won’t make contact unless you “modify” it, see¬†http://www.eevblog.com/forum/microcontrollers/3m-soic8-clip-waste-of-timemoney/msg33462/?PHPSESSID=e4d9fa7c85d3aee85d389405447973cc#msg33462

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Things I do after installing Ubuntu

1. Disable ipv6 and apparmor for speed up


ipv6.disable=1 apparmor=0

to linux command line in /etc/default/grub then run


and reboot.

2. Disable wireless power saving on battery, because frankly 1 to 2 hundred milliseconds response time is too slow when you’re 20 feet from the access point.

Edit /usr/lib/pm-utils/power.d/wireless and replace any lines containing “power on” with “power off”. Not any update to pm-utils will overwrite this file and change the setting back.

3. Install Chromium as it is quite a bit faster and nicer to use than Firefox.

Remembering to keep Firefox around for the odd site that won’t work in Chromium e.g. some java based sites.

4. Add “noatime” and “commit=900” to fstab.

Gives performance increase and saves SSDs by not writing to the journal all the time.

Install HP Laserjet CP1215/foo2zjs in Linux Mint Debian Edition

The in-Distro version of foo2zjs has dependency problems at time of writing. Use the one from the foo2zjs home page. From your home directory in a terminal:-

wget -O foo2zjs.tar.gz http://foo2zjs.rkkda.com/foo2zjs.tar.gz
tar zxf foo2zjs.tar.gz
./getweb 1215
sudo make install

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Migrating from Chrome to Chromium

To get a more open source experience I changed from Chrome to Chromium for Linux. It left me without my bookmarks, etc. though. The user data for Chrome is stored in ~/.config/google-chrome. To get my data into Chromium I simple moved the files from there into ~/.config/chromium. Job done.