diff --git a/sys/src/libjson/json.c b/sys/src/libjson/json.c
index 62113468a..1056ac5d0 100644
--- a/sys/src/libjson/json.c
+++ b/sys/src/libjson/json.c
@@ -153,7 +153,7 @@ lex(Lex *l)
 						r *= 16;
 						if(c >= '0' && c <= '9')
 							r += c - '0';
-						if(c >= 'a' && c <= 'f')
+						else if(c >= 'a' && c <= 'f')
 							r += c - 'a' + 10;
 						else if(c >= 'A' && c <= 'F')
 							r += c - 'A' + 10;