Unfortunately yes, you still need to install a custom rom to get rsap working with OPX.
However, as Cyanogenmod rom is far better than Oxygen, it is worth playing the game
Be carefull when flashing your phone, backup it and fully load the battery before.
To have rsap working, do the following steps only once:
- Install Cyanogenmod 13 I've used 2013.0-20160528-Nightly, I do not know if it can be done with the latest one. I recommend to do the procedure with this cyanogen version, then update to the latest one thought OTA when all the steps are completed (including the beer, so you can have 2 beers...or more
- Install the modified kernel (with fastboot) (, MD5 sum is f821d9531499329e26e0682c1044a99d)
- Enable Root access (by setting "root access" option to "applications & ABD) in "developper options" menu)
- Install rsap system files thanks to "rsap install application"
- Install rsap application
- Have a beer
After each Cyanogen update, no need to reinstall the modified kernel, just open "rsap install application" to re-install rsap files and thats all!