Android Backup & Restore

You’ve just gotten your shiny new Android Phone, and you want to migrate to it. There are several options, including Titanium Backup to move stuff, but Google also has you covered (party): Android Backup & Restore. You can find this setting on your phone, under “Settings” and “Backup & Restore”. This thing backups several things, but far from all:

  • Your installed (Google Play) apps
  • WiFi accesspoints & passwords (if this is a good thing, is another question)
  • Certain application settings (this is application dependent)
  • Probably more…

This feature is known to be a bit of a battery drainer, so many people leave it off by default. This is ofcourse a PITA when you want to move – as your phone won’t start backing up immediately after you tap the option.

Luckely, you can trigger this manually: you need to activate USB Debugging on your phone, and then start a new ADB shell with the command aplty called adb shell
Then you can play around with the backup manager, bmgr. In most cases you’ll just want to trigger a backup immediately: bmgr run
This will trigger the backup manager to run a backup, send all your stuff over to the cloud. Give it a few minutes, and then add your Google Account to your new phone, and presto – it’s all there. Sortof.

For a full overview what you can do with bmgr, see the android developer webpage.

OpenWRT, Atheros & channel availability

If you’re living outside the US, and you’re using OpenWRT (a fantastic 3rdparty opensource firmware for many routers), you might have noticed that not all the WiFi channels which are legally allowed in your region are actually available for you to choose from.

This is a known issue, and stems from the fact that the OpenWRT images are built without CONFIG_ATH_USER_REGD=y (which allows overriding the wifi-card builtin default regulatory domain), so that the builds are compliant with the regulations of the US. (see trac ticket 6923)
If you pick another region in the settings, the ROM will pick the most restrictive of the two – in my case this means that WiFi channels 12 and 13 are not available to choose from.

There are two ways to get around this:

  • Building OpenWRT from source, and enabling this option
  • Using reghack to patch the drivers (see the README on how to do this)

I only recently learned of reghack (thanks, Stijn!) which works nicely ;)

XPS13, Linux, suspend and Intel Rapid Start Technology

As an addendum to my previous post on how to install Debian Sid on the XPS13, I’ve been having issues with suspend – the laptop would sporadicaly not go to sleep properly on lid close, or it wouldn’t come out of suspend afterwards.

I seem to have found a solution for both:

  • The laptop suspends correctly after upgrading the xserver-xorg-video-intel driver to the version available in experimental, and upgrading the kernel to kernel 3.9 rc 6 (which contains a bunch of fixes for Ivy Bridge, and the touchpad driver comes built-in). You’ll need to manually build this kernel as detailed in the Debian Kernel Handbook.
  • The not waking up part seems to have been caused by the Intel Rapid Start Technology (iRST in short), which basically is an (S4) hibernate triggered from the BIOS a short while after you put the laptop in (S3) suspend (you never see this from the OS side). The laptop will dump the memory contents to a special partition on the harddisk and shutdown completely. Very good for battery life, less so for waking up from suspend – sometimes it would be instantaneously, sometimes it would take a minute or two, and at other times it just wouldn’t do anything.
    After disabling this in the BIOS the laptop works as expected.
    (you can find more about iRST and Dell here)

Dell XPS 13 and Debian Sid

I purchased a Dell XPS 13 Ultrabook, to replace my ageing Apple Macbook 2,1. After six years of daily use, it’s (over)due to retire.

The reasons for not going for another Apple product:

  • I don’t agree with their behaviour in the various markets where they’re competing. It’s competing, Apple, not sueing for the smallest tidbit. Want to survive, innovate.
  • I no longer use OSX. Linux all the way, baby.
  • Seriously overpriced hardware for the same specifications. The only thing going for them is the screen resolution on the Retina models.

Extra reasons to go for the XPS 13:

  • Nice extra discount through work.
  • Very nice screen resolution on a 13″. Not quite up to retina specs yet, but this is good enough ;)
  • Ultrabook. Light. Long battery.
  • SSD, and loads of RAM

Spec comparison:

Apple Macbook 2,1Dell XPS 13 (2013)
Screen resolution:1200×8001920×1200
Storage:80GiB HDD256GiB SSD
CPU:Core2Duo 2GHzCore i5-3337U
Battery life:3-4 hours7-8 hours

The laptop arrived in a sortof-stylish black Dell box, unfortunately taped over with all kinds of deliver stickers. Oh well.

The box it was shipped in

The box it was shipped in

Inside you can see the box for the power cord, and the box with the actual laptop. Nicely packaged, pluspoints here, Dell ;)

Nicely packaged

Nicely packaged

Fancy Dell box containing the actual laptop

Fancy Dell box containing the actual laptop

The actual laptop. Wrapped in plastic, protected with foam

The actual laptop. Wrapped in plastic, protected with foam

All unpacked and ready to rock!

All unpacked and ready to rock!

It’s also a bit smaller than my old Macbook, although they’re both rated as being 13″ laptops.

Dell XPS13 on top of my Macbook 2.1. Bit smaller. A lot lighter.

Dell XPS13 on top of my Macbook 2.1. Bit smaller. A lot lighter.

Unfortunately, the laptop I got shipped originally had some issues: plenty of backlight bleeding, and a wifi module that was broken – it would detect a wireless network for 1-2 minutes after powerup, and then nothing.
I called Dell, they sent round a technician… but after this repair, it was completely dead. So they shipped me a replacement, on which I’m typing this blog-post.

Back to the actual laptop – it’s a nice piece of hardware, but the Core i5 version comes shipped with Windows 8, unfortunately. Luckely for us, it’s easy to put something else on (or next) to it ;)
(note: the Core i7 version is the ‘developer’ version, which is shipped with Ubuntu! :D It’s called Project Sputnik)

Steps to shrink the Windows 8 partition (if you want to keep it around, otherwise you can just wipe the entire SDD. Don’t forget to first create some recovery images, though!):

  • Disable hibernate: open a command prompt (in admin mode) and type: powercfg /H off
  • Disable the windows pagefile (you can do this in Control Panel – System – Advanced Settings)
  • Disable system restore (ditto)

A reboot later, you should be able to shrink the partition to the minimum required (I left it around 50GiB). If you don’t disable all that crap, Windows will only allow you to shrink down to around 110GiB, which is frankly ridiculous.
You can enable everything again after shrinking the partition.

This will leave us with a nice amount of storage to put Linux on.

Now, download the Debian Testing latest weekly dvd 1 for amd64. You’ll also need a USB stick of 8GiB (4.5 is needed). Format that stick as FAT32, and copy the content of the DVD image on the stick (not the actual ISO).

After this is done, you can reboot the laptop. When you see the Dell logo flash on the screen, quickly hit F12 (repeatedly). This will present you with the boot menu, where you can choose what to boot. I recommend to pick ‘Legacy mode’, and from there ‘USB storage’. Normally this will boot the Debian installer from the memory stick.

To install Debian, I refer you to the Debian Installation Manual, an excellent document that details all the steps. Just be careful not to wipe out the existing Windows partition, should you want to keep it ;)

Some time later, you’ll get to reboot the system, and Debian should be the default choice to boot with the UEFI boot manager ;)

At this point it’s also highly recommended to add unstable and experimental sources to your /etc/apt/sources.list file – the testing distribution just installed it – ahem – slightly outdated in software terms, and we’ll definitely need a new kernel.

Add this to /etc/apt/sources.list (replacing XX with your two-letter country code):

deb sid main contrib non-free
deb experimental main contrib non-free
deb-src experimental main contrib non-free

Do an apt-get update && apt-get dist-upgrade and you’re good to go on the packages. For a newer kernel, do apt-cache search linux-image and check for the latest kernel release, right now that is linux-image-3.8-trunk-amd64, which you can install with apt-get install -t experimental linux-image-3.8-trunk-amd64.

Now, to fix some of the issues I’ve encountered:

Non-functional wifi
On another laptop (or in Windows), download the firmware-iwlwifi package. Install it – a reboot later you should be able to configure the wireless interface. You might also need wpasupplicant if you use encryption on your network. (I’m lazy, so I downloaded all the packages needed for wicd and configured stuff that way.)

Laptop wakes from suspend out of the blue
I’ve encountered a few times that the machine came out of suspend without any trigger from me – highly annoying (and dangerous, should this happen while the machine is in a backpack and start to heat up). I’ve found this Bug report on Launchpad about it. The fix seems to be to disable “Smart Connect” in the BIOS. I’ve tried it here, seems to work.

Touchpad isn’t recognized as a touchpad
The patches to support the touchpad are on route to be included in kernel 3.9, but (at the time of writing) that one hasn’t been released yet. So we need to take the latest kernel available in Debian Experimental (3.8.5) and patch this with the driver. Luckely Debian has The Linux Kernel Handbook which explains how to do all this the proper Debian way ;)

First, install the necessary build packages: apt-get install build-essential fakeroot devscripts && apt-get build-dep linux-3.8
Next, get the kernel sourcecode: apt-get source linux-image-3.8-trunk-amd64 -t experimental
Download the patches too: wget '' -O /usr/src/cypress-touchpad-v7.patch and wget '' -O /usr/src/cypress-touchpad-v7.patch
Now, go to the source directory cd /usr/src/linux-3.8.5 and execute the script to rebuild the kernel with the two patches:  bash debian/bin/test-patches ../cypress-touchpad-v7.patch ../increase-struct-ps2dev-cmdbuf-to-8-bytes.patch
Now go eat a pizza, make some coffee, solve a theorem or so. It’ll take a bit. When it finishes, you’ll have another shiny kernel in /usr/src, which you can install with dpkg -i linux-image-3.8-trunk-amd64_3.8.5-1~experimental.1a~test_amd64.deb And Bob’s your uncle.

Brightness level doesn’t stick after a suspend/resume
For this I made a custom suspend-resume hook for pm-utils. Add the following script as /etc/pm.d/sleep.d/00backlight



case $1 in
echo “Saving backlight brightness level…”
cat $SYSFS/actual_brightness > $TMP
if [ -e $TMP ]; then
echo “Restoring backlight brightness level…”
cat $TMP > $SYSFS/brightness
rm $TMP
echo “No brightness level save file found.”
echo “Dunno what you’re trying…”
exit 1

This script will read the backlight brightness level upon suspend, and store it in a file in /var/tmp. Upon resume, the value is read from the file and the brightness level set to it.

The permanent fix is also scheduled for kernel 3.9.

Unreadable (way too tiny) fonts in applications
This is actually a drawback from having a high-resolution screen: a lot fits on it, but the fonts are tiny.
I had the issue mostly in Opera, IceDove (a rebranded Thunderbird) and XTerm, my X Terminal of choice.

In Opera you can just set the default zoom level. I put this at 120%, everything is readable now.
For Thunderbird, I can advise installing the ViewAbout extension, and then looking in View -> ViewAbout -> about:config for the setting layout.css.devPixelsPerPx, and setting this to “1.2”.
For XTerm, I added this to .Xresources (in my home directory):

XTerm*faceName: Dejavu Sans Mono
XTerm*faceSize: 11

so that XTerm uses the Dejavu Sans Mono truetype font, size 11, instead of the default.