diff --git a/armsrc/lfops.c b/armsrc/lfops.c
index 6ab87fec0..066363164 100644
--- a/armsrc/lfops.c
+++ b/armsrc/lfops.c
@@ -383,7 +383,7 @@ void ModThenAcquireRawAdcSamples125k(uint32_t delay_off, uint32_t period_0, uint
             } else {
                 // if field already on leave alone (affects timing otherwise)
                 if (off) {
-                    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+                    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_ADC_READER_FIELD);
                     LED_D_ON();
                     off = false;
                 }
@@ -407,7 +407,7 @@ void ModThenAcquireRawAdcSamples125k(uint32_t delay_off, uint32_t period_0, uint
         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc->divisor);
     }
 
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_ADC_READER_FIELD);
 
     // now do the read
     DoAcquisition_config(false, 0);
@@ -1515,7 +1515,7 @@ void CmdIOdemodFSK(int findone, uint32_t *high, uint32_t *low, int ledcontrol) {
  */
 
 void TurnReadLFOn(uint32_t delay) {
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_ADC_READER_FIELD);
 
     // measure antenna strength.
     //int adcval = ((MAX_ADC_LF_VOLTAGE * AvgAdc(ADC_CHAN_LF)) >> 10);
@@ -2451,7 +2451,7 @@ void Cotag(uint32_t arg0) {
 # define OFF(x)  { FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); WaitUS((x)); }
 #endif
 #ifndef ON
-# define ON(x)   { FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD); WaitUS((x)); }
+# define ON(x)   { FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_ADC_READER_FIELD); WaitUS((x)); }
 #endif
     uint8_t rawsignal = arg0 & 0xF;