Default Preferred Network settings not sticking

does anyone have aio? everytime i reboot my phone it drops to 3g from 4g in the actual settings under mobile networks>preferred network type..i have to keep going back to *#*#4636#*#* to change from wcmda preferred to lte/gsm .ive tried several different modems same thing and lte and 4g is widely avail in the locations i used the phone (houston).. oh and also i have checked build.prop and preferred is set to 9 with ro.telephony.default_network and tried two different combinations with telephony.lteOnCdmaDevice=0 telephony.lteOnGsmDevice=1 also tried changing that 0 to 1