diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index 78892e1da8..a012d0a583 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -223,7 +223,7 @@ func (c *cache) generate(dir string, limit int, test bool) {
 			size = 1024
 		}
 		// If we don't store anything on disk, generate and return.
-		if dir == "" {
+		if dir == "" || limit <= 0 {
 			c.cache = make([]uint32, size/4)
 			generateCache(c.cache, c.epoch, seed)
 			return
@@ -305,7 +305,7 @@ func (d *dataset) generate(dir string, limit int, test bool) {
 			dsize = 32 * 1024
 		}
 		// If we don't store anything on disk, generate and return
-		if dir == "" {
+		if dir == "" || limit <= 0 {
 			cache := make([]uint32, csize/4)
 			generateCache(cache, d.epoch, seed)