diff --git a/src/cfgparse-global.c b/src/cfgparse-global.c
index 9e7e3324b..a80ac854f 100644
--- a/src/cfgparse-global.c
+++ b/src/cfgparse-global.c
@@ -515,12 +515,12 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 
 		if (alertif_too_many_args(0, file, linenum, args, &err_code))
 			goto out;
-		global.tune.options &= GTUNE_USE_FAST_FWD;
+		global.tune.options &= ~GTUNE_USE_FAST_FWD;
 	}
 	else if (strcmp(args[0], "tune.disable-zero-copy-forwarding") == 0) {
 		if (alertif_too_many_args(0, file, linenum, args, &err_code))
 			goto out;
-		global.tune.options &= GTUNE_USE_ZERO_COPY_FWD;
+		global.tune.options &= ~GTUNE_USE_ZERO_COPY_FWD;
 	}
 	else if (strcmp(args[0], "cluster-secret") == 0) {
 		blk_SHA_CTX sha1_ctx;