If you want install custom firmware in your Xperia Arc then you need to unlock the bootloader of the device. Bootloader is area which will give you access to the devices ROM this enabling you to remove the firmware that is installed and install a custom firmware.
By default the bootloaer is locked and you won’t be able to root or even install a custom firmware. If you do unlock the bootloader then you shouldn’t opt for the OTA (over the air) updates from Sony Ericsson as it may cause the device to crash.
It is very easy to unlock the bootloader of your Xperia Arc and we have prepared a guide which will enable you to unlock the bootloader and give you the ability to install custom firmware and also root your device.
Procedure For Unlocking the Bootloader
1. You need to make sure that the bootloader can be unlocked and you can do that by checking the service menu of your device. To access the service menu on your dialer input *#*#7378423#*#*
2. Once in the service menu tap on service info > configuration> rooting status.
3. If you see that bootloader unlock allowed says yes then you can continue with further steps and if it says no then you won’t be able to unlock your device and can’t proceed further.
4. Now on your PC click on continue to unlock the bootloader
5. The information that pops up read through it and once you’re sure click on Yes i’m sure
6. After scrolling through the legal terms click on yes
7. In this part you need to enter your name, email address and your 14 digit phone’s IMEI number and the two CAPTCHA and then clik on submit
8. To view your IMEI number input *#06# on your phones dialer
9. You need to download and install the Android SDK
11. Place the unzipped file in step 10 into the usb_driver folder and when asked replace the old file that is available there. If you can’t find the usb_driver folder then you need to install the Google USB driver package in your Android SDK
12. Turn off your phone and push the unlock button and hold it as you connect your phone to the PC with the USB cable
13. Once connected on your PC it will ask for the USB driver so navigate to the usb_driver folder and select the file android_winusb.inf-file and select android boot loader interface file
14. Open command prompt and enter the android SDK folder and type fastboot.exe -i 0x0fce getvar version and make sure that you get a response back which will show that your phone is connected to the PC properly.
15. Now to unlock the bootloader enter the commands fastboot.exe -i 0x0fce oem unlock 0xKEY the key is the unlocked bootloader key that you obtained in the beginning.
There you go now you have unlocked the bootloader of your device and you can proceed to root your device and even install custom firmware on your Xperia Arc. But be warned that unlocking the bootloader will cause you to void the warranty of your device so you do it at your own risk.
Do let us know if you were successful and also which custom firmware you installed on your device.