You have to update the build.prop correctly, and move certain telephoney files needed for CDMA RIL plus the files needed by the triumph for RIL. The problem is finding out the right combination of files. The thing is that if you have the right combination, but have one extra telephoney file that is not needed RIL may still work; but if you put in a extra telephoney file that the ROM doesn't like then its gonna complain about it ( The process com.android.phone has stopped unexpectedly. Please try again ).
This is the correct line for RIL
ro.telephony.default_network=4
but if you don't have the right CDMA telephoney files then you will get that process close error. So to stop it & be able to make calls(but no 3G), change/add this line to build.prop
ro.telephony.default_network=0
Now you won't get that process close error anymore, but as soon as you have the right combination of telephoney files and you still have that line set as '0' process close error will come up; but when you change it back to '4' with the right combination of telephoney files you will get RIL.
Though the thing is, MIUI & CM is different from Stock ROMs since their AOSP and the files have "differences" in them. So there's a high chance that the ROM will still complains 'The process com.android.phone has stopped unexpectedly. Please try again' even though you have the right combination of telephoney files.
These are the main files(and their smaller versions(the ones with $)) that will have to be added to the ROM
/telephony/RIL.smali,
/telephony/RILConstant.smali,
/telephony/ServiceStateTracker.smali,
/telephony/BaseCommands.smali,
/telephony/dataconnection.smali,
/telephony/dataconnectiontracker.smali,
/telephony/cdma/cmdadataconnection(tracker).smali,
/telephony/cdma/cdmaservicestatetracker.smali,
/telephony/cdma/CDMASMSDispatcher.smali,
I was going to make my own GB ROM but I don't have enough time to look through a bunch of telephoney files. I think I fixed SMS though, but I need static to test it.