diff --git a/ipmitool/include/ipmitool/ipmi_constants.h b/ipmitool/include/ipmitool/ipmi_constants.h
index 23f291b..820cdac 100644
--- a/ipmitool/include/ipmitool/ipmi_constants.h
+++ b/ipmitool/include/ipmitool/ipmi_constants.h
@@ -81,6 +81,8 @@
 #define IPMI_SET_IN_PROGRESS_IN_PROGRESS  0x01
 #define IPMI_SET_IN_PROGRESS_COMMIT_WRITE 0x02
 
+#undef IPMI_CHANNEL_MEDIUM_IPMB
+
 #define IPMI_CHANNEL_MEDIUM_RESERVED	0x0
 #define IPMI_CHANNEL_MEDIUM_IPMB	0x1
 #define IPMI_CHANNEL_MEDIUM_ICMB_1	0x2