The Linux kernel for Sony Xperia phones is open source. So nobody is stopping you from compiling your own custom kernel. All you need is a Linux machine, the kernel sources and a couple of tools.
I will explain the steps needed to build, package and flash a custom kernel by using the Xperia T (LT30p) as an example. The steps should be pretty similar for all other modern Xperia phones.
If you are using Linux kernel 3.4, especially on Android, and you are having troubles mounting windows or samba shares, and you are in a hurry, please skip to section 2 or the conclusion at the end. I just need to tell a little story first.
That’s how it’s supposed to be: You take out your Android phone. Mount a windows share to a directory of your liking and start accessing your files from any app you like. Yes, eat that, iPhone. Welcome to the 21st century. At least that’s how it used to be on my Xperia T until I updated the firmware to a newer version.
To be more precise, you need a rooted Android phone. And an app like CifsManager. It’s pretty easy. You can enter a number of windows shares, including user name and password if necessary, and the paths you want them to be mounted to. From now on, you can mount and unmount the shares with a single click. Really neat.
Then one day, I updated the firmware of my Xperia T from 7.0.A.3.195 (Android 4.0.4) to 9.1.A.0.489 (Android 4.1). And the days of happy networking with windows were gone. CifsManager stubbornly denied mounting with an “Invalid argument” error. A very helpful error, I must say.
After hours of googling around, I found many articles, telling me that the linux kernel of the new firmware is probably missing CIFS support. If I am lucky, somebody will create a CIFS kernel module, which could be loaded with insmod. Again many hours later I realized that nobody seems to have done that for my phone. So I gave up, hoping that the issue would be fixed in another firmware.