diff --git a/swtpm-utils/getcapability.c b/swtpm-utils/getcapability.c
index 7359ba3..17b4324 100644
--- a/swtpm-utils/getcapability.c
+++ b/swtpm-utils/getcapability.c
@@ -480,7 +480,8 @@ int main(int argc, char *argv[])
 				  }
 
 				  if (c) {
-				      char pcrmap[4], *pf;
+				      char pcrmap[4];
+				      unsigned char *pf;
 
 				      memcpy(pcrmap, ndp.pcrInfoRead.pcrSelection.pcrSelect,
 					     ndp.pcrInfoRead.pcrSelection.sizeOfSelect);