[Sprint Samsung Galaxy S6] koop1955:
I have been asked by several people, on the forums and via PM. I thought that I would offer a step-by-step guide.

Will This Trip Knox? Yes, it will. Installing a custom recovery such as TWRP will definitely trip Knox. From what I have read installing a ROM, even through FlashFire, will trip Knox, as will flashing a kernel.

You Don't Seem To Care About Knox That is correct. To this point the only downside is that I won't be able to use Samsung Pay and I don't plan on that anyway. BUT.....if you do care and Knox matters, stop reading now and stick with stock.

I will also recommend that you grab ODIN and a stock TAR file for your phone. You can always find the latest firmware at SamMobile, but will need to create an account and free downloads are speed capped. It will be SLOOOOW. But you will get a zip with the file that you need inside. Good to have in case of accident. Here is where I got mine: http://www.sammobile.com/firmwares/download/47474/G920PVPU1AOE2_G920PSPT1AOE2_SPR/

That said.....assume that you have a rooted S6. Install TWRP Manager from the Play store, ignore anything it says about an SD card and click on "Install TWRP." The version that you are looking for is "zerofltespr.img." You can also download that from here https://twrp.me/devices/samsunggalaxys6sprint.html and use Flashfire to install. Reboot into recovery (see http://www.androidexplained.com/galaxy-s6-recovery-mode/ for an explanation) and make sure that TWRP is installed. If TWRP doesn't come up, make sure that you used the correct file and try again.) Now you are ready to begin.

1) The ROM that I used is the SAC23 ROM from here: http://xdaforums.com/sprint-galaxy-s6-edge/development/sac23ram9200srintdeoxedmoddedv1-t3107342 Download that and copy to your phone. You should also grab the "Recent apps fix long press on home" zip file from the bottom of that post.

2) You will also NEED (!!!!!) a kernel that is designed for the S6, otherwise you will bork your phone. I use (and recommend) the Ktoonsez kernel located here: http://xdaforums.com/sprint-galaxy-s6/orig-development/kernel-kt-sgs6-ocv-ktweaker-t3093009 Grab that and copy to your phone.

3) For fingerprint recognition and private mode, you will need the Aroma installer from here: http://xdaforums.com/showpost.php?p=60112854&postcount=2 If you use the Aroma installer (and I don't so I have no experience) be sure that those are the only two things that you install.

UPDATE 7/1/2015 Just had a report that fingerprint is working with this kernel: http://xdaforums.com/sprint-galaxy-s6/development/kernel-kernel-t3146127

Anyone interested should read all posts for that kernel before flashing.

Once you have those files on your phone, you are ready to begin.

Return to recovery mode. Before you do anything else....Click on "Backup." Accept the default settings and let it do its thing. I always name my backups....calling this Stock is probably a good idea. Once that is done, if you break things, you can return to this.

Okay, now go to Wipe. The old-timers will disagree, but most of the time the default "Factory Reset" is all that you need. If you are paranoid (and who isn't?) after this you can go to Advanced and choose Dalvik Cache, Cache, Data and System. But I rarely do this anymore. Complete guide for using TWRP is here: http://www.androidtipsandhacks.com/root/twrp-the-complete-guide-to-using-recovery-on-android/

Now go back to the main screen and select Install. You can select multiple zips. Flash the ROM, the kernel and that Recent Apps zip file. Be sure to set the kernel to flash after the ROM. Or you can flash them one at a time.

Once done, reboot phone and if all went well, you will see a new boot animation. First boot will take a while, let her go.

You should have a clean build so remember that you will need to reset Developers options, security (for allow Unknown sources) and other stuff.

With the Ktoonsez kernel, you will have the KTweaker app, very useful. If it doesn't install for you (and it didn't for me) the APK is located inside the zip file that you downloaded at S6\KT-SGS6-LP5.0-TW-G920P-05.28.2015.zip\system\app\ Extract that and install. I use downloaded Profiles a lot.

If all is well, but the fingerprint and private mode settings are things that you use, go back into Recovery and select ONLY those two items. I'll state again, I don't use them, have never flashed the Aroma installer and can't offer any help. I have seen that they work for some people, not for others..../me shrugs. I can't help with that.

I also use the Wicked One Theme from [MENTION=500949]dazedandconfused[/MENTION] who is a master. See http://xdaforums.com/sprint-galaxy-s6-edge/themes-apps/theme-wicked-one-theme-s6-s6-edge-t3129822 for the theme and instructions. Be sure to follow the instructions about having the Urban theme from the Theme Store installed first. But this theme makes me very happy.

That is everything that I know....which goes to show how little I know!

EDIT: Missed a step....DOH!.... if you are using TWRP you should flash the zip file found here to address the Deep Sleep issue: http://xdaforums.com/showpost.php?p=60385577&postcount=56

Happy ROM-ing.