diff --git a/src/common.c b/src/common.c
index 5829ec6..9dd73d3 100644
--- a/src/common.c
+++ b/src/common.c
@@ -68,6 +68,9 @@ static inline int fromhex (const char c)
     if (c>='A' && c<='F')
         return c-'A'+10;
 
+    if (c>='a' && c<='f')
+        return c-'a'+10;
+
     return -1;
 }