diff --git a/chain/vm/vmi.go b/chain/vm/vmi.go
index f7fc366ee..e7d9ab92d 100644
--- a/chain/vm/vmi.go
+++ b/chain/vm/vmi.go
@@ -19,7 +19,7 @@ type Interface interface {
 	Flush(ctx context.Context) (cid.Cid, error)
 }
 
-var experimentalUseFvm = os.Getenv("LOTUS_USE_FVM_EXPERIMENTAL") == "1"
+var experimentalUseFvm = os.Getenv("LOTUS_USE_FVM_TO_SYNC_MAINNET_V15") == "1"
 
 func NewVM(ctx context.Context, opts *VMOpts) (Interface, error) {
 	if opts.NetworkVersion >= network.Version16 {