[Samsung Galaxy Ace 4] doesntexits:
CyanogenMod is a free, community built, aftermarket firmware distribution of Android 5.1.1 (LP), which is designed to increase performance and reliability over stock Android for your device.

#include <std_disclaimer.h>
/*
* Your warranty is now void.
*
* I am not responsible for bricked devices, dead SD cards,
* thermonuclear war, or you getting fired because the alarm app failed. Please
* do some research if you have any concerns about features included in this ROM
* before flashing it! YOU are choosing to make these modifications, and if
* you point the finger at me for messing up your device, I will laugh at you.
*
*/

BEFORE INSTALLING THIS ROM, MAKE SURE YOUR DEVICE MODEL IS THE SAME AS TITLE

IF YOU ASK ANY QUESTIONS LIKE "IS THIS FOR MODEL BLABLABLA" THEY WILL BE ALL IGNORGED

CyanogenMod is based on the Android Open Source Project with extra contributions from many people within the Android community. It can be used without any need to have any Google application installed. Linked below is a package that has come from another Android project that restore the Google parts. CyanogenMod does still include various hardware-specific code, which is also slowly being open-sourced anyway.

We'll not support users and answer questions from users which:

are running a custom kernel

have flashed mods

modified system files

didn't follow our intructions word by word

are unfriendly

And most important: DON'T READ THE OP

What's working:

Wifi (connection, tethering, etc)

Bluetooth

Camera, video codecs

RIL (Calls, SMS, mobile data)

Storage (both internal and external)

MTP storage (both internal and external)

Offline charging

zRAM (compressed-RAM swap)

GAPPS

Tethering (USB, Wifi, Bluetooth)

GPS

Sound recording

Torch (flashlight)

BUGS/Not working :

There're lots of bugs, but main are

(SM-G313ML) Mobile data doesn't work

Switching to other fonts will get bootloops after restart. In this case, if you use TWRP recovery, go to File Manager >> delete "themes" from /data/system would help you escape this without factory reset

Distorted Bluetooth sound on calls

First time installing CyanogenMod 12.1 to your Galaxy V, or coming from another ROM:

Install TWRP Recovery

Reboot into Recovery using 3-button-combo (Vol-up+Home+Power)

Do a Nandroid backup! (Optional and only if you weren't running TouchWiz before)

WIPE (wipe data/factory reset + wipe cache partition + format /system partition)*

Install the ROM from sdcard using TWRP Recovery

Optionally install the Google Apps ( get it here: https://opengapps.org ) (pico GAPPS recommended)

INSTALLATION VIDEO

[YOUTUBE]Jp9UMPGwVVk[/YOUTUBE]

If you're going to reuse our work, be kind and give proper credits

This is the only payment we're really demanding and we deserve it to be mentioned because of the countless hours we've put into this project.

Open-source doesn't mean "out of respect"

In Downloads section

Mirror: Beta 3 Update 1

XDA:DevDB Information

CyanogenMod 12.1, ROM for the Samsung Galaxy Ace 4

Contributors

doesntexits, ngoquang2708

Source Code: https://github.com/ngoquang2708/android_device_samsung_vivalto3gvn/tree/cm-12.1

ROM OS Version: 5.1.x Lollipop

ROM Kernel: Linux 3.10.x

ROM Firmware Required: Stock 4.4.x

Based On: CyanogenMod

Version Information

Status: Beta

Current Beta Version: 3 Update 1

Beta Release Date: 2016-05-28

Created 2016-02-16

Last Updated 2016-06-12