[Galaxy A3, A5, A7, A8, A9 General] Jonny_Hood:
Bevor you do something with your Device do a Backup of all your Data (Contacts, Pic´s ect.) outside of your Device (in a Cloud or on your PC)​

I'm not responsible for bricked devices, dead SD Cards, broken phone chargers etc.​

You do all at your own Risk!​

If you are new, just work the first 3 steps from top to bottom.​

Flash Root & Odin3:

At the https://autoroot.chainfire.eu/ site you can Download the the Root File for your Device (Link to A300FU). When you Downloaded the "CF-Auto-Root-xxx.zip" File unzip it. In this zip you will find the Odin3xxx.exe and the Root .tar.md5 File

You need this Odin3 tool also for TWRP and going Back to Stock Rom

For Root: Make sure your device is in ODIN download mode (you can get there by holding VolDown+Home+Power when the device is turned off), then start the included Odin3xxx.exe file, press the PDA/AP button, select the Root .tar.md5 file, and click Start, never interrupt this action! You can find more detailed instructions and assistance at [CENTRAL] CF-Auto-Root Thread

Flash TWRP:

You can Download the TWRP File at the [RECOVERY][ROOT][TWRP 3.0.2-1]Samsung Galaxy A3(2015) SM-A300F/FU/G/H/M Thread. I recommend the Build from Post 80 it has working MTP & OTG for the FU Device!

To Install Start download mode (you can get there by holding VolDown+Home+Power when the device is turned off), then start the Odin3xxx.exe file, press the PDA/AP button, select the TWRPxxx.tar file, and click Start, never interrupt this action! After Reboot you can get there by holding VolUp+Home+Power when the device is turned off.

There are also a TWRP 2.8.7.0 and a TWRP 3.0.0-0 but both have small bugs so i recommend TWRP 3.0.2-1 only if you have Problems try to downgrade

TWRP Bugs:

TWRP 2.8.7.0 Can only Install CM12.1 ROMs, it has no MTP & no OTG

TWRP 3.0.0-0 Can only Install CM13 ROM & it has no MTP but OTG is Working

TWRP 3.0.2-1 Can not install [MENTION=369083]cbolumar[/MENTION] ROMs and the Build from Opening Post has no OTG

TWRP 3.1.0 Only tested with LineageOS, it still has no MTP!!!

Flash a Custom ROM:

You can Install a ROM now with TWRP you can enter TWRP by holding VolUp+Home+Power when the device is turned off.

In TWRP IT IS HIGHLY RECOMMEND TO DO FIRST A BACKUP! (I Recommend to placed at the SD Card)

Backup -> Storage : Micro SDcard -> Ok -> [x] Boot, [x] System, [x] Data, [x] Cache, [x] Recovery, [x] EFS, [x] MODEM, [x] APNHLOS -> Swipe to Backup

If anything goes wrong you can easy Restore your Device in TWRP without losing anything, so it's also recommended to Backup your Custom ROM

Now you need your Custom Rom, Google Apps like Opengapps for ARM and i recommend latest Magisk[/URL, OR (if you prefer) [URL="http://download.chainfire.eu/supersu"]SuperSU to Manage Root Access.

Place this zip Files at your Device (I Recommend to placed at the SD Card)

Now you enter TWRP and go to:

Wipe -> Advanced Wipe -> [x] Dalvik / ART Cache, [x] System, [x] Data, [x] Cache -> Swipe to Wipe

Now go back to main menu and select:

Install -> Storage : Micro SDcard -> Ok -> now choose your ROM zip first, you can "Add More Zips" and choose Gapps zip and if you want you can Add direct Magsik OR SuperSU zip as well -> Swipe to Confirm Flash

After placing files the Device need a Reboot, at the First Start it will Install your Rom, so be patiently at first start!

Flash Xposed:

Magisk user on Android M (6.x) or better follow this Thread [2018.5.6][Magisk] Systemless Xposed v89.3/v90.2-beta3 (SDK 21-27) by topjohnwu

SuperSU user on Android M (6.x) or better follow this Thread [OFFICIAL] Xposed for Lollipop/Marshmallow/Nougat/Oreo [v90-beta3, 2018/01/29]

info:

SDK 21: Android 5.0 | SDK 22: Android 5.1 | SDK 23: Android 6.0 | SDK 24: Android 7.0 | SDK 25: Android 7.1 | SDK 26: Android 8.0 | SDK 27: Android 8.1

at CM12.1 ROM's Offical Xposed works fine.

Download the "sdk22-arm" zip, and Install it with TWRP first start need a long time! be patient!

After the Framework is installed you install the "XposedInstaller" apk, done.

For stock rom you should visit [UNOFFICIAL] Xposed for Samsung Lollipop by arter97 but it´s for deodex'ed ROMs for this you should visit [Deodex][SM-A300] Deodex Thread for Samsung Galaxy A3

Flash Stock ROM:

Download your Firmware at Sammobile than i recommend you to Wipe all (Advanced Wipe) in TWRP except the SDcard!

Boot your Device in ODIN download mode (you can get there by holding VolDown+Home+Power when the device is turned off), then start the Odin3xxx.exe file, press the PDA/AP button, select the .tar.md5 file, and click Start, never interrupt this action!

After doing this you lose TWRP and Root so if you need it you have to install it new.

You should not try to Flash 4.x ROMs it could Brick your Device!

With a Stock Marshmallow ROM it is recommended to use a Custom Kernel

A300FU / A300Y Custom Kernel:

Kraken Kernel R1 from [MENTION=3120910]bulgar[/MENTION]

Will only work with at Stock Marshmallow (6.x) ROM

-soon- LineageOS Support

hadesKernel from [MENTION=4658360]corsicanu[/MENTION]

Will only work with at Stock Marshmallow (6.x) ROM

A300FU / A300Y Modification:

[MOD][Stock Rom] Enable More Quick Tiles on Touchwiz from [MENTION=5819220]astrit1[/MENTION]

Will only work with at Stock Lollipop (5.x) ROM

There are still the following Bugs:

No Bugs

[ROM][A300FU][6.0.1] [GS]Mod from [MENTION=4704860][GS][/MENTION]

There are still the following Bugs:

Private Mode Not Work

WHASISTROM We have a simple stock rom [A300FU/OL3/OJ5] from [MENTION=6512075]nowheel[/MENTION] Discontinued

A300FU / A300Y Custom ROMs:

Check also in All Samsung Galaxy A3 (2015)'s ROMs Thread from [MENTION=8260066]Falaysia[/MENTION]

-Recommended-

LineageOS 15.1 Unofficial for Samsung Galaxy A3 (2015) from [MENTION=7315425]vl_w[/MENTION]

There are still the following Bugs:

* FM works only on headphones

* Unable to capture video in 1080p (only 720р works)

* Incorrectly work with secondary sim (incall sound issues)

* On FU and H doesn't adjusting flahlight brightness

* On H incorrectly detecting battery temperature

* Hardware keystore doesn't work (only software)

* NFC sometimes doesn't work

LineageOS 14.1 Unofficial for Samsung Galaxy A3 from [MENTION=7315425]vl_w[/MENTION]

There are still the following Bugs:

no Bugs

CyanogenMod 12.1 for Samsung Galaxy A3 from [MENTION=5197763]evilracer123[/MENTION] Discontinued

In the Opening Post is not the latest Build!

This is the post with the last Build from 19th January 2016 ;)

There are still the following Bugs:

-SoD´s (can be Fixed for the most users by using CPU Awake - Wake Lock with Unlimited time & Activate on Reboot (Clean Master turns it off btw) or Wake Lock - PowerManager with "PARTIAL_WAKE_LOCK")

-Preview in stock camera (can be Fixed by change Resolution to 16:9 in Settings)

-FM Radio not Working (can be Fiexed by using Spirit2)

-Folders are not displayed correctly with LCD density 260 DPI (can be Fixed by changing it to 240 DPI)

-When screen is off touch buttons still working, at touch the phone vibrates.

-USB Conection adb only working MTP, PTP, OTG or UMS not Working (you can use MTP and OTG in TWRP 3.0.2-1 Recovery)

-for some users "com.qualcomm.timeservice" fc time to time (can be Fixed by disable the automatic services in Time settings)

-for some users gps are not Working

at my device:

-Cast screen is not Working

CyanogenMod 12.1 Resurrection Remix from [MENTION=369083]cbolumar[/MENTION] Discontinued

There are still the following Bugs:

-SoD´s (can be Fixed for the most users by open integrated Kernel Adiutor and allow Root access)

-Preview in stock camera (can be Fixed by change Resolution to 16:9 in Settings)

-FM Radio not Working (can be Fiexed by using Spirit2)

-When screen is off touch buttons still working, at touch the phone vibrates.

-USB Conection adb only working MTP, PTP, OTG or UMS not Working (you can use MTP and OTG in TWRP 3.0.2-1 Recovery)

at my device:

-Cast screen is not Working

Note: can only installed with TWRP 2.8.7.0 after installing you can upgrade your Recovery to TWRP 3.0.2-1

CyanogenMod 12.1 from [MENTION=369083]cbolumar[/MENTION] Discontinued

There are still the following Bugs:

-SoD´s (can be Fixed for the most users by using CPU Awake - Wake Lock with Unlimited time & Activate on Reboot (Clean Master turns it off btw) or Wake Lock - PowerManager with "PARTIAL_WAKE_LOCK")

-Preview in stock camera (can be Fixed by change Resolution to 16:9 in Settings)

-FM Radio not Working (can be Fiexed by using Spirit2)

-When screen is off touch buttons still working, at touch the phone vibrates.

-USB Conection adb only working MTP, PTP, OTG or UMS not Working (you can use MTP and OTG in TWRP 3.0.2-1 Recovery)

-for some users "com.qualcomm.timeservice" fc time to time (can be Fixed by disable the automatic services in Time settings)

at my device:

-Cast screen is not Working

Note: can only installed with TWRP 2.8.7.0 after installing you can upgrade your Recovery to TWRP 3.0.2-1

Hope this will Help to answering the most Questions :D

By the way i'm not a Dev, i'm only a regular user that wants to help!

You will also get Information and Help at the Everything Samsung a3 Thread :good: