diff --git a/GCodes.cpp b/GCodes.cpp
index 852a087..b29f19c 100644
--- a/GCodes.cpp
+++ b/GCodes.cpp
@@ -1344,7 +1344,7 @@ void GCodes::SetMACAddress(GCodeBuffer *gb)
 	{
 		if(ipString[sp] == ':')
 		{
-			mac[ipp] = strtol(&ipString[spp], NULL, 0);
+			mac[ipp] = strtol(&ipString[spp], NULL, 16);
 			ipp++;
 			if(ipp > 5)
 			{
@@ -1358,7 +1358,7 @@ void GCodes::SetMACAddress(GCodeBuffer *gb)
 		}else
 			sp++;
 	}
-	mac[ipp] = strtol(&ipString[spp], NULL, 0);
+	mac[ipp] = strtol(&ipString[spp], NULL, 16);
 	if(ipp == 5)
 	{
 		platform->SetMACAddress(mac);