Sony Xperia S was the first Xperia smartphone to feature the Sony branding after Sony acquired Sony Ericsson in the year 2012. Despite the branding, the smartphone was actually developed by Sony Ericsson and only carried the Sony logo on the front since the acquisition had been completed before the device could be announced. So the first Sony branded Xperia smartphone was in fact the last Sony Ericsson flagship smartphone. Due to these reasons, the smartphone managed to gain more attention than earlier Xperia flagship smartphones from Sony Ericsson and was quite a successful device for Sony. Thanks to its popularity, the device attracted a lot of developer attention as well and over the years the development scene for the device has managed to remain quite active. Although the device doesn’t enjoy as much attention now, there are still a number of custom ROMs available for the Xperia S. Recently the device has received some Android 5.1 Lollipop ROMs as well, based on the CM 12.1 base.
The uCyan 12.x custom ROM for the Sony Xperia S has been developed by Senior XDA member mickybart. The ROM is actually just an Unofficial CM 12.1 port, as uCyan simply means ‘unofficial CyanogenMod’. So this ROM is basically just plain vanilla CM 12.1 with no additional features or tweaks. The ROM is currently not the most stable around and there are a few minor bugs and issues that need to be fixed. However, the developer has been making very good progress and has fixed a number of bugs with CM 12.1 for Sony Xperia S. The ROM supports overclocking as well, although it is recommended that you do not attempt overclocking with this ROM since it isn’t completely stable to begin with. When the developer irons out all the issues and the ROM becomes perfectly suitable as a daily driver ROM, you could try overclocking if you wish to. However, even now you could use this ROM as a daily driver if you can live with the minor bugs and issues. Feedback on the ROM from users is quite positive so far, so this is one of the best ROMs currently available for the Sony Xperia S if you wish to try out the latest Android 5.1 Lollipop version on your device.
You can get this custom ROM installed on your Sony Xperia S by following the guide below and doing everything required to get your Xperia S ready for the custom ROM installation. Once you have taken care of everything, you can begin installing this custom ROM.
Before getting to the other requirements, it is important that you first back up all the important data that you will lose during the installation of this custom ROM. The things that you will lose are your contacts, SMS, installed apps, games, and app data that is stored in the system and data partitions on the device. All of these will have to be backed up using a backup and restore app. Sony stock ROM does come with a backup and restore app, so if you are using a stock or stock based custom ROM on your Sony Xperia S, you can use the Sony backup and restore app in order to get all the data backed up on the device. If you are on an AOSP based ROM or any other ROM that doesn't include Sony apps, you will have to look for a backup and restore app on the Google Play Store. When you search for a backup and restore app, you will find results for various apps such as Titanium Backup, Helium, and MyBackup. These three are among the most highly rated apps that are available, so you won't really go wrong if you choose any of them to back up your data. Once the data has been backed up, we would suggest you consider getting a Nandroid backup of your ROM done. Whatever ROM you may be using currently, you will be able to revert to it easily in future if you get a Nandroid backup via recovery. If you need help regarding the Nandroid backup, you can read the tutorial posted at this link.
Have you unlocked the bootloader of your Sony Xperia S? If you haven't yet done it, you will have to unlock the bootloader of your smartphone now if you really do want this custom ROM to be installed on your Xperia S. The AOSP based uCyan Android 5.1.1 Lollipop custom ROM can be installed only on Xperia S smartphones that have an unlocked bootloader. On a device with a locked bootloader, it will not be possible to get this custom ROM installed. You shouldn't really have to worry about anything before getting the bootloader unlocked as the device is quite old now, so it must have run out of warranty already. So you have nothing to lose by unlocking the bootloader. A custom recovery needs to be installed on your Xperia S as well, so that you can flash the ROM ZIP file and get this custom ROM installed on the device. However, it is recommended that you install TWRP 22.214.171.124 or 126.96.36.199 before installing this ROM, and not any other custom recovery that is available for the Sony Xperia S. Root access is required as well, so make sure the smartphone is rooted before you continue any further.
Whether you are currently running a stock based ROM or an AOSP based ROM, you must ensure that the USB Debugging option is enabled under developer options. This option can be found on all Android 4.1+ versions. So if you are on Android 4.0 or lower firmware, we suggest you upgrade to Android 4.1 or newer firmware.
The last but certainly not the least important requirement is to charge the battery on your Sony Xperia S till the 60% mark before you begin the uCyan custom ROM installation. Especially on an older device such as the Xperia S, it can be very risky to attempt the installation with low battery charge.
How to Upgrade Sony Xperia S to Android 5.1 Lollipop Using uCyan 12.1 Custom ROM
- Two files need to be downloaded to your PC in order to get this custom ROM installed on your Sony Xperia S. The first is the uCyan 12.1 ROM ZIP file and the other is the GAPPS ZIP file that will give you all the Google apps and services on this ROM. The latest build of uCyan custom ROM can be downloaded from this link. As for GAPPS, you can find the latest Android 5.1.1 Lollipop GAPPS from this link.
When the uCyan 12.1 ROM ZIP file and the GAPPS ZIP files are downloaded to your computer, you will have to connect your Sony Xperia S to the PC so that the files can be moved to your device. Once you connect your Xperia S to the PC, cut/copy the two files from your PC and then paste them on the device's internal memory. Do not place the files in any sub folder as you will have to browse the storage to select these files later.
Wait for the files to be transferred and then disconnect your Xperia S from your PC and press the power button to turn it off. Once the device has turned off, boot it into the recovery mode.
When your device successfully boots to the recovery menu, you will have to select the 'wipe data factory reset' option first so that a factory reset can be done. That's just the first step though. There are still more things to be done. After performing a factory reset, you will notice that the recovery menu now shows options for wiping the cache, dalvik cache, system, and data partitions. Select each of those options individually to perform a full wipe before the uCyan 12.1 custom ROM can be installed on your Xperia S.
When you finish with the wiping process in the previous step, you can start the flashing process by returning to the main recovery menu screen. Now select the 'Install zip from SD card' option and then browse the storage of your Xperia S to choose the uCyan 12.1 custom ROM ZIP file. That's it. You can now select the flash option and then wait for the whole process to finish. It won't take very long though, just a few seconds and it should be done.
Now the GAPPS ZIP file will have to be flashed on your Xperia S so that you can access the Google Play Store, YouTube, Gmail, Google Maps, and other essential Google apps and services with this custom ROM. Just choose the GAPPS ZIP file from the device's storage and flash it in the similar way as the ROM ZIP file above.
Finish the installation process by selecting the 'reboot system now' option in the main recovery menu.
Now when your Sony Xperia S boots up, you will have the uCyan 12.1 custom ROM up and running on your smartphone. However, we would like to warn you that the first boot will take quite a bit longer than the usual boot times you may be used to. So you will have to be quite patient for the ROM to boot up.
In case anything goes wrong or you face any major bugs with this ROM, please report them at the official ROM thread at this link.