[Q] How do I flash a rom and still retain data

[urbanman2004]

I am wanting to install Scott's CleanROM 4.0 on my my 32GB Nexus 7 Wifi tablet. I have rooted the tablet using the Wugs toolkit and have TWRP Recovery installed and created a back up on an external USB stick. My ultimate goal is to be able to charge my phone while using OTG/MHL at the same time with my OTG Y-adapter. If there is a better rom I can use or an easier way to achieve my objective, by all means feel free to advise me. Thanks in advance.

 

[tshot]

Clean Master has a feature where you can back up apps. Then restore them. Also, when moving ROMs, your pictures and Videos will stay.(Only if you factory reset. DO NOT WIPE THE VIRTUAL SD CARD.)
If you do need to wipe your SD, then back up your Pictures, Video's and other stuff on your PC then restore them. Back your apps up with an app Although, I personally don't mind re-installing all my apps.

 

[urbanman2004]

Clean Master has a feature where you can back up apps. Then restore them. Also, when moving ROMs, your pictures and Videos will stay.(Only if you factory reset. DO NOT WIPE THE VIRTUAL SD CARD.)
If you do need to wipe your SD, then back up your Pictures, Video's and other stuff on your PC then restore them. Back your apps up with an app Although, I personally don't mind re-installing all my apps.

Thanks for informing about Clean Master, but that's diverting from my question at hand. I am already aware that when changing roms that my files/pics will still be intact. Since CleanRom is essentially an AOSP rom, I just did a Nandroid backup on my USB-OTG, Factory Reset: Wipe Data /Cache/ Dalvik, and restored the Data only from my Nandroid backup (although I understand it's not recommended) on the new rom to recover my settings and apps. Maybe my question was confusing, so let me correct myself. What I was asking was: is there a Kernel I can use that enables me to use USB-OTG and charge my device simultaneously. I notced that Timur has a Rom but I rather use a Kernel achieves this end result alongside CleanRom. I tried installing ElementalX 1.8 and it won't show up after reboot everytime I install it.