diff --git a/src/pulses.cpp b/src/pulses.cpp
index b74582c8a..33ec0ad8b 100644
--- a/src/pulses.cpp
+++ b/src/pulses.cpp
@@ -215,7 +215,7 @@ FORCEINLINE void setupPulsesPPM()
 }
 
 #if defined(PXX)
-pm_uint16_t CRCTable[] PROGMEM =
+const pm_uint16_t CRCTable[] PROGMEM =
 {
     0x0000,0x1189,0x2312,0x329b,0x4624,0x57ad,0x6536,0x74bf,
     0x8c48,0x9dc1,0xaf5a,0xbed3,0xca6c,0xdbe5,0xe97e,0xf8f7,