diff --git a/armsrc/fpgaloader.h b/armsrc/fpgaloader.h
index 66cca0510..21731b571 100644
--- a/armsrc/fpgaloader.h
+++ b/armsrc/fpgaloader.h
@@ -74,6 +74,7 @@ extern void switch_off(void);
 // Options for the HF reader, correlating against rx from tag
 #define FPGA_HF_READER_RX_XCORR_848_KHZ				(1<<0)
 #define FPGA_HF_READER_RX_XCORR_SNOOP				(1<<1)
+#define FPGA_HF_READER_RX_XCORR_QUARTER				(1<<2)
 // Options for the HF simulated tag, how to modulate
 #define FPGA_HF_SIMULATOR_NO_MODULATION				(0<<0) // 0000
 #define FPGA_HF_SIMULATOR_MODULATE_BPSK				(1<<0) // 0001