Flashing a new kernel and ROM on an Xperia Arc

While there are a plenty of tutorials on how to flash a new kernel/ROM onto my phone available on the XDA developers forum, fact of the matter is that I don’t visit very often. The result is that every few months when I feel like ‘upgrading’ my phone, I have to read/search through a mountain of posts to get the information I need. Being the lazy kind of individual, I’ve decided to make my own notes on how to do the upgrade. For anyone reading this, please note: these instructions are for an unlocked Xperia Arc (international release).

Flashing the kernel

For my new kernel I’m going to go with DooMKernel v22. The binaries can be downloaded from the following thread (near the end of the second post);

http://forum.xda-developers.com/showthread.php?t=1172885

The kernel image needs to be flashed from a connected PC, but there are a few extra modules that need to be on the SD-card. Copy them over before starting the kernel flash. Next, we’ll need the “fastboot pack”. Here’s a download link,

http://unlock-bootloader.com/wp-content/plugins/download-monitor/download.php?id=21

fastboot is a utility that lets you flash a new kernel image to your android phone (I suspect that this is a tool that comes with the android SDK and someone has just re-packaged it into a smaller download). The phone must be placed in “fastboot mode” first. For the Xperia Arc, turn off the phone. Then press and hold the menu button while its attached to a PC (via USB). A blue light should appear on the side of the phone if it worked. The PC (assuming windows) should start installing drivers now. Instructions on this can be found here,

http://forum.xda-developers.com/showthread.php?t=1299729

After that’s done, just drag the kernel to be flashed onto the “Drop_here_to_flash_kernel.bat” file. It will do the flashing and the terminal window should close itself.  To install the modules, enter recovery mode on the phone (press and hold the menu button during phone boot) and select the option to flash the modules zip file. With his latest kernel, there are a few extra features in recovery. You can read about those here,

http://forum.xda-developers.com/showpost.php?p=22686721&postcount=2

Flashing a new ROM

Considering the ‘trouble’ we just went through to install a new kernel on the device, the process of installing a new ROM is relatively simple. In a nutshell;

  1. Copy ROM zip to sdcard
  2. Boot phone in recovery
  3. Do a factory reset, clear the cache partition and wipe the dalvik+battery stats
  4. Install ROM from zip.

That’s it. For more details you can check out this forum post (second thread);

http://forum.xda-developers.com/showthread.php?t=1508585

WARNING NOTE:

For reasons I do not understand, it appears impossible to install the fastboot drivers on windows 8 (64bit). These are needed by the fastboot utility, so without them, you will NOT be able to flash a new kernel image to the phone. I’ve spent a lot of time trying to get the drivers to work, but have given up in despair. The same drivers work in Win7 (64bit), so I’m going to take this as proof that Microsoft is trying to stifle android development.

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