Despite not packing impressive specifications, the Samsung Galaxy Ace line proved to be quite successful for the company and the Galaxy Ace 3 was among the most successful models in the series yet. Launched in the year 2013, the Samsung Galaxy Ace 3 came with slightly better specs than previous Galaxy Ace smartphones, which was part of the reason behind its success. While the hardware was improved over the previous generation, Samsung didn’t pay as much attention to the software aspect. The smartphone launched with Android 4.2 Jelly Bean out of the box and is still stuck on the same Android version till date. It didn’t receive a single major Android update, despite the relatively powerful internals, especially on the LTE variant. Unfortunately, it is only the LTE variant of the Galaxy Ace 3 that has received good support from the developer community as the 3G model is powered by a Broadcom chip, which limits developer attention. However, the LTE variant has a number of custom ROMs available, including an Unofficial CM 12.1 based on the latest Android Lollipop 5.1.1 version.
The Unofficial CM12.1 port for the Samsung Galaxy Ace 3 GT-S7275 comes from XDA senior member kotzir and is currently in Beta version. This means the ROM isn’t completely stable right now, and you will need to deal with a number of bugs and issues. While previous builds of the ROM had a long list of bugs, the developer of the ROM has managed to fix most of these bugs and the only major bug that remains to be fixed now is NFC. Since not many users use NFC on a regular basis, this should not be a major issue for most of you. Most of the other functions work just fine, including the sensors, Wi-Fi connectivity, Bluetooth, phone calls, mobile data, GPS, video playback, and the camera. So you can use this ROM as a daily driver if you can live with the few minor bugs. The ROM doesn’t come with any additional tweak and features over the CM 12.1 base, but it does come pre-rooted. So you will not have to flash anything in order to gain root access with this ROM. After your device boots up, you will simply need to go to Development Settings and enable root access to get root access.
The custom ROM is no doubt quite impressive and is oen of the best custom ROMs available for the Galaxy Ace 3 if you wish to try out the latest Android version on your smartphone. The tutorial below explains all the requirements and the steps involved in the installation process, so make sure you read it completely and follow all the suggestions mentioned. We would also like to warn our readers that this ROM is only meant for the Samsung Galaxy Ace 3 LTE model (GT-S7275). If you own any other variant of the Galaxy Ace 3 such as the 3G variant, you should not attempt to install this ROM on your device as doing so will cause your device to get bricked.
Whenever you install a new custom ROM on your Samsung Galaxy Ace 3 or any other Android device that you own, it is important to perform a clean installation of the ROM. And when you have to perform a clean installation, it is required that you save a backup of your data in advance. A clean installation of a custom ROM requires you to perform a full wipe of the data and system partitions on your smartphone, which means all data that is stored in those directories will be wiped. Some of the important data that is stored there include your contacts list, SMS, apps, and app data. To back it all up, you will need to take the help of a backup and restore app from the Google Play Store. You can download and install any app from the Google Play Store to take a backup of your data, but we usually recommend sticking to some of the more popular apps such as Helium, MyBackup, and Titanium Backup. Root access is required as well, so we suggest rooting your Galaxy Ace 3 before moving on to downloading and installing a a backup and restore app. Once the backup of your data is ready, you can also take a Nandroid backup of your current ROM. This can be considered optional, if you are sure about the fact that you will be using the Unofficial CM 12.1 custom ROM on your Galaxy Alpha for a long time. But if you do not wish to continue using this ROM as a daily driver, then a Nandroid backup is definitely recommended. Perform all steps mentioned at this link to back up your ROM.
You may have come across the warning from manufacturers that unlocking the bootloader of your smartphone will void the warranty on your device. Unlocking the bootloader is required when you have to flash AOSP based custom ROMs on your device, such as the Unofficial CM 12.1 ROM that we're dealing with today. But when devices get old and the warranty runs out, there is no other risk involved when unlocking your device's bootloader. And that means most Samsung Galaxy Ace 3 owners can unlock the bootloader right away, with nothing to worry about. The next requirement for getting this custom ROM installed is the latest version of TWRP Recovery. Even though there are other custom recoveries available for the Galaxy Ace 3, the developer of this ROM suggests using TWRP Recovery for flashing this ROM. Even if you have an older version of TWRP Recovery installed on your Galaxy Ace 3, updating to the latest available version is a necessity. We have already mentioned it once, but let us remind you once again that root access is required for you to flash this custom ROM on your smartphone. So make sure you root your Galaxy Ace 3.
If you have finished rooting your Samsung Galaxy Ace 3, you can proceed to enable USB Debugging under Developer Options. Just go to Settings - Developer Options and then scroll down to the USB Debugging option and check the box next to it.
We have almost finished preparing your Samsung Galaxy Ace 3 for the Unofficial CM 12.1 custom ROM installation process. You can continue to the ROM installation below after you check the battery charge status. This is very important since you shouldn't try to install a custom ROM on your smartphone if the battery doesn't have much charge left. Continue only if your Galaxy Ace 3 has 60% or higher battery charge left, if not, charge it first.
How to Update Samsung Galaxy Ace 3 to Android 5.1.1 Lollipop Using Unofficial CM 12.1 custom ROM
- Begin the ROM installation by download the ROM ZIP file from this link. Downloading the ROM ZIP file alone isn't going to be enough though, you will need to get the GAPPS ZIP file downloaded to your computer as well. GAPPS for Android 5.1.1 Lollipop can be downloaded from this link. The GAPPS ZIP file is not part of this custom ROM but needs to be installed so that you can access Google apps and services that do not come by default with this custom ROM.
In order to move the above two files to your Galaxy Ace 3, connect the smartphone to your computer with the provided USB cable. Now move them both to the internal memory's root directory.
Since we have to continue with the installation process now, remove your Galaxy Ace 3 from the computer and power it off. When your smartphone turns off, get it to boot into recovery mode.
When your Samsung Galaxy Ace 3 boots into the recovery mode, you will need to begin the full wipe process by selecting the 'wipe data factory reset'. Confirm factory reset and wait a few seconds for it to finish. Then, select the 'advanced options' to wipe the dalvik cache, cache, data, and system partitions. This could perhaps be considered to be one of the most important steps in the installation process and we would suggest you never forget to perform a full wipe before installing any custom ROM. Only when you are upgrading to a newer build of this ROM, you will not have to perform a full wipe. Instead of wiping everything, upgrading to a newer build only requires wiping of the cache and dalvik cache.
Begin flashing the Unofficial CM 12.1 custom ROM ZIP file on your smartphone by returning to the main recovery menu and then choosing the 'Install zip from SD card' option. Browse the device's storage to select the ROM ZIP file and start flashing the file.
When the ROM ZIP flash is complete, it is now the turn of the GAPPS ZIP file to be flashed in order to get all the Google apps and services installed to the ROM. Same exact procedure as above, except for the fact that you will be choosing the GAPPS ZIP file this time.
You have successfully installed this Android 5.1.1 Lollipop custom ROM on your Samsung Galaxy Ace 3 now. Select the 'reboot system now' and exit the recovery.
The first time this custom ROM boots up, it might take up to a few minutes. So please keep this in mind and have patience. If you decided to try this custom ROM only for a few days, you can restore your Nandroid backup via recovery and return to your previous ROM. Detailed instructions on the process can be found in the same link above that we asked you to visit to learn how you can back up your ROM. But if you think you can continue using this custom ROM as a daily driver, do check for updated ROM build releases by visiting this link.