diff --git a/mission/acs/gyroAdisHelpers.cpp b/mission/acs/gyroAdisHelpers.cpp
index 5dd3a217..5c1446cc 100644
--- a/mission/acs/gyroAdisHelpers.cpp
+++ b/mission/acs/gyroAdisHelpers.cpp
@@ -59,7 +59,7 @@ void adis1650x::prepareWriteRegCommand(uint8_t regStart, uint16_t val, uint8_t*
     return;
   }
   outBuf[0] = regStart | adis1650x::WRITE_MASK;
-  outBuf[1] = val & 0Xff;
+  outBuf[1] = val & 0xff;
   outBuf[2] = (regStart + 1) | adis1650x::WRITE_MASK;
   outBuf[3] = (val >> 8) & 0xff;
 }