Speed up Android by sacrificing your “better” RNG

Sometimes Android can just be sluggish. If you want to try a little trick, replace your Random Number Generator.

There are two RNGs for Linux based systems, /dev/random and /dev/urandom. The latter is the weaker but faster (especially a “nonblocking”) one. As you probably won’t need extra high security for your daily tasks (unless you do work for some intelligence agency or are a nasty bad guy) there is only little risk incurred.

You need to be root for this:

# rm /dev/random
# ln -s /dev/urandom /dev/random

This tweak does not survive a device reboot.

Please tell me if you feel any difference (especially for Google+)!

Android 4.x, nativer E-Mail Client und ZIP-Anhänge

Fehlermeldung: “Sie können diese Datei nicht öffnen oder speichern, da diese Art von Anhang möglicherweise schädliche Software enthält.” (ENG: “You can’t save or open this file because this type of attachment might contain malicious software”).

Der native Google-Mailclient wurde wohl von einem ex-Microsoft Outlook Produktmanager entwickelt? Jedenfalls will ich alle Anhänge herunterladen können. Sonst hätte ich mir auch ein Windows/Apple-Tablet kaufen können.

Folgende Anhänge werden geblockt laut Android-Quelltext:

public static final String[] UNACCEPTABLE_ATTACHMENT_EXTENSIONS = new String[] {
// File types that contain malware
“ade”, “adp”, “bat”, “chm”, “cmd”, “com”, “cpl”, “dll”, “exe”,
“hta”, “ins”, “isp”, “jse”, “lib”, “mde”, “msc”, “msp”,
“mst”, “pif”, “scr”, “sct”, “shb”, “sys”, “vb”, “vbe”,
“vbs”, “vxd”, “wsc”, “wsf”, “wsh”,
// File types of common compression/container formats (again, to avoid malware)
“zip”, “gz”, “z”, “tar”, “tgz”, “bz2”,

Hier erwarte ich ganz klar mehr Flexibilität und ich denke, dass ich damit nicht alleine stehe. Schreibt eure Kommentare an die Android-Entwickler bitte auf folgender Seite: http://code.google.com/p/android/issues/detail?id=27245

Google Nexus 7 (and others) – Slow Write Speed Fix

The newest release of Android (4.1.2) introduced a fix for the slow flash/eMMC write speed (also known as “lag problem”). But installing the update alone isn’t enough, the eMMC controller needs to know the truly empty addresses on the flash. Although this will resolve over time by itself, you can speed up the process to have your devices running at the speed just as it was freshly unboxed.

Here’s how to do it!


  • root access
  • Android 4.0.4 (older untested)

Get your ADB or terminal shell ready for this:

user@computer:# mount -o remount,rw,discard /data
user@computer:# dd if=/dev/zero of=/data/deleteme bs=64k ; rm /data/deleteme

You can also do this for the different partitons (cache, system, …) just replace the “/data” strings above.

By the way it’s most likely that your device will not respond to your input – just let it sit around, do not reset or force anything. It will just take take some time to get the flash filled. As soon it’s done your device will be responsive and a real roadrunner again.

[Q] What if I do not have root?
Well, then you can only make use of the procedure with Android 4.1.2 and the /data or /cache partitions. Just omit the mount-command and you will be fine.

[Q] I can’t write to the /data partition without root!
Just use /sdcard – it’s the same.

[Q] This takes forever – low long shall I wait?
Depends on your device. My Google Nexus Q handles about 1GB/hour, Nexus 7 can do about 1GB/min in best case – but don’t count on it.

[Q] Help! My device does not respond to input!
I’ve just said so! The fill up of the storage will really take some time and slows down the device to a crawl. However, you might want to try IO-renicing the dd-command with “ionice” to prevent this behaviour.


Update 2013: By now you can also use LagFix Free. It is faster than using the described method.


Google Nexus Q: First Storage Benchmark

Oh dear, the random write performance is bad… But this is to be queued to the bottom of the todo list, but I assume it won’t be hard to get a decent performance out of it.

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