Folks at XDA have made Samsung Galaxy J5 2015 pre rooted and debloated ROM and it is based on stock android 5.1.1 firmware J500FNXXU1AOI1_J500FNDBT1AOI2_J500FNXXU1AOI1. Here are its features. Galaxy J5 2015 Pre rooted, Debloated ROM is an excellent firmware for those who are not looking for extra features but for those who are looking to stick to stock ROM but want it pre rooted, zipaligned, debloated, dodexed and knox removed.
* Based on firmware J500FNXXU1AOI1_J500FNDBT1AOI2_J500FNXXU1AOI1
* Pre-Rooted with SuperSU (v2.66)
* Busybox installed (v1.24.1-osm0sis)
* Zipaligned all system apps for better use of memory
* Deodexed
* Debloated = more free RAM, more storage to play with
* Knox removed
* Faster boot and shutdown
* Faster than stock.
Here are its installation instructions:
1. Download the rom and put it on your External SD Card ( make sure you have enough space).
2. Download this TWRP recovery: TWRP recovery here.
3. Download ODIN program. I’m using v3.09
4. Enable the unlock bootloader option at Developer Settings (if you can’t see Developer Settings, then go to Settings > About phone and tap 7 times build number).
5. Reboot your phone in download mode by keeping pressing Power button + home button + volume DOWN button at same time for few seconds. After an blue screen will appear, press volume up button.
6. Connect your phone with usb cable to your PC.
7. Open ODIN program and an number should appear at ID:COM. If it doesn’t, then make sure that the phone usb drivers are installed.
8. Click on AP or PDA and choose the TWRP recovery you’ve downloaded and click START. Wait until the process finish.
9. Now go to TWRP recovery by keeping pressing Power button + home button + volume UP button at same time for few seconds.
10. Choose Wipe, then Advanced wipe and choose Dalvik Cache, System, Data and Cache and then Swipe to wipe.
11. Now choose Install and go to the place where you did put the ROM and choose it. Wait till installation finish and DON’T REBOOT YET.
12. Flash GAPPS. I use Open Gapps, ARM 5.1.1 pico version. http://opengapps.org/
13. Wipe dalvk cache & cache.
14. Reboot & WAIT 5-10 minutes until it boot. Only first boot is longer. NOTE: When you reboot, if it ask you for SuperSU > choose "do not install".
15. If you followed all the steps carefully, then everything will be OK.