[XPERIA X10 Q&A, Help & Troubleshooting] Dr Goodvibes:
You should see a blue light(some Kernel use bright green) when booting which indicates the time you should press the 'back' button on the X10i to enter xRecovery or CWM recovery.

Those CM10 based ROM use CWM I believe and not xRecovery.

So using xRecovery to install a CM10 ROM would be wrong.

You'd probably have to use flashtool to flash a CM10 Kernel with CWM recovery and then boot straight into CWM Recovery, some CM based Kernel may not come with CWM recovery installed..

OR you could use flashtool to install CWM recovery and from flashtool and set the X10i to reboot into CWM recovery.

Then from the CWM recovery menu...

>Reset to factor settings

>Clear Dalvik cache

>Install the CM10-ROM.zip from CWM recovery (and any other additional zip files)

Power off (that may mean pulling out the battery)

Re-flash the CM10 kernel via flashtool again and reboot.

Mostly a clean GB v2.3.3 fw (SEUS/PC companion) has the correct build.prop details so that an install of a CM10 ROM via CWM recovery can be done without having to previously have a CM10/CM9 ROM installed.

Out of interest what are you hoping to gain by installing a CM10 (Android 4.1.2) ROM???

What feature(s) in CM10 do you require???

I can't be sure and it's only from memory[citation needed], but CM10 and CM10.1 ROM as I remember, use more memory and thus less memory for your apps.

What music player will you use on your XPERIA X10i/a??????????

The new Sony Music player (XPERIA T+) does now support .flac[citation needed], but you lose .wma. I'm not sure if ClearAudio+ has been ported(or even if it's possible) on XPERIA X10i hardware.

So will you be playing .flac encoded audio??? AND if you're building JUST a music player, the Sony Music player will not be enough(Me thinks)

I settled on .ogg encoded music myself. Which I think is the most flexible with good quality over a wide range of audio output devices.

At home it's all streamed from my NAS.

I have not read the CM10 comment/changelog in detail, but I don't remember seeing the 'throw' menu option listed as a working feature on a XPERIA X10i, which would imply some form of WiFi-Direct is functional on the XPERIA X10i using 802.11g.

That's one of the few reasons I could think of for using Android 4.1.2 - 4.2 on an XPERIA X10i as a music player.

I have the Sony connect feature working on my XPERIA X10i v2.3.3, but that uses SMB, not WiFi-Direct.

You can install xLoud and BRAVIA engine on GB 2.3.3 without any problems, maybe not BRAVIA engine v2 though, but then you're only using the XPERIA X10i as a music player any way.

So, as you read above, I'm still trying to steer you towards GB 2.3.3 ROM without the added complexity/complications of JB 4.1.2 on an XPERIA X10i, BUT as just a music player a CM10 based ROM should still work fine.

Just to refresh I have DoomKernel v6 (Clocked at 1113MHz) with XPERIA S add-ons using stock GB 2.3.3 with all the bloatware removed, which is basically what DonutHD is.

I use Neutron Music player.

And the other quite good thing of my current setup is the battery life(Mugen Power 1800mAh) is pretty good and ranges from 2-3 days depending on use. Can last 4-6 days if only used to check email. :) I have an XPERIA LT26i too.

There are many other good ROM/Kernel/Apps available for the XPERIA X10i too, but the above are the ones I have settle on.