diff --git a/documentation/en/local-dev-net.md b/documentation/en/local-dev-net.md
index 24c732db7..3382b6471 100644
--- a/documentation/en/local-dev-net.md
+++ b/documentation/en/local-dev-net.md
@@ -6,6 +6,14 @@ Build the Lotus Binaries in debug mode, This enables the use of 2048 byte sector
 make 2k
 ```
 
+Set the `LOTUS_SKIP_GENESIS_CHECK` environment variable to `_yes_`. This tells your
+Lotus node that it's okay if the genesis being used doesn't match any baked-in
+genesis.
+
+```sh
+export LOTUS_SKIP_GENESIS_CHECK=_yes_
+```
+
 Download the 2048 byte parameters:
 ```sh
 ./lotus fetch-params 2048
diff --git a/node/modules/chain.go b/node/modules/chain.go
index 904c9f23b..0c9943b21 100644
--- a/node/modules/chain.go
+++ b/node/modules/chain.go
@@ -3,6 +3,7 @@ package modules
 import (
 	"bytes"
 	"context"
+	"os"
 
 	"github.com/ipfs/go-bitswap"
 	"github.com/ipfs/go-bitswap/network"
@@ -127,8 +128,18 @@ func LoadGenesis(genBytes []byte) func(dtypes.ChainBlockstore) Genesis {
 func DoSetGenesis(_ dtypes.AfterGenesisSet) {}
 
 func SetGenesis(cs *store.ChainStore, g Genesis) (dtypes.AfterGenesisSet, error) {
-	_, err := cs.GetGenesis()
+	genFromRepo, err := cs.GetGenesis()
 	if err == nil {
+		if os.Getenv("LOTUS_SKIP_GENESIS_CHECK") != "_yes_" {
+			expectedGenesis, err := g()
+			if err != nil {
+				return dtypes.AfterGenesisSet{}, xerrors.Errorf("getting expected genesis failed: %w", err)
+			}
+
+			if genFromRepo.Cid() != expectedGenesis.Cid() {
+				return dtypes.AfterGenesisSet{}, xerrors.Errorf("genesis in the repo is not the one expected by this version of Lotus!")
+			}
+		}
 		return dtypes.AfterGenesisSet{}, nil // already set, noop
 	}
 	if err != datastore.ErrNotFound {