diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1f721db9378..669129d5af5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@
 
 ## Improvements
 
+- Reduce size of embedded genesis CAR files by removing WASM actor blocks and compressing with zstd. This reduces the `lotus` binary size by approximately 10 MiB. ([filecoin-project/lotus#12439](https://github.com/filecoin-project/lotus/pull/12439))
+
 # Node v1.29.0 / 2024-09-02
 
 This is a Lotus Node only release, which includes a variety of new features, improvements, and fixes, particularly focused on enhancing ETH RPC functionality. Key highlights of this release include:
diff --git a/build/bootstrap/butterflynet.pi b/build/bootstrap/butterflynet.pi
index 7289b5d95f8..06129878d59 100644
--- a/build/bootstrap/butterflynet.pi
+++ b/build/bootstrap/butterflynet.pi
@@ -1,2 +1,2 @@
-/dns4/bootstrap-0.butterfly.fildev.network/tcp/1347/p2p/12D3KooWGW6xMTpjEBqndYkqytbu8PWfJmpK4wKLLLNSkXL2QZtD
-/dns4/bootstrap-1.butterfly.fildev.network/tcp/1347/p2p/12D3KooWFGz9HegR3Rjrtm8b9WXTM6E3kN1sdd6X1JztuCgQaZSB
+/dns4/bootstrap-0.butterfly.fildev.network/tcp/1347/p2p/12D3KooWF76a8Avv74CV55noqKd5rHsM8uwFYhaW4PhMhuE4PQsP
+/dns4/bootstrap-1.butterfly.fildev.network/tcp/1347/p2p/12D3KooWCN1G8gK5HXQNDFKxAVmF6bpg436uVyNYFgiX94ZHCPjj
diff --git a/build/buildconstants/params_butterfly.go b/build/buildconstants/params_butterfly.go
index afcad287cae..e976e01f94a 100644
--- a/build/buildconstants/params_butterfly.go
+++ b/build/buildconstants/params_butterfly.go
@@ -22,7 +22,7 @@ var NetworkBundle = "butterflynet"
 var ActorDebugging = false
 
 const BootstrappersFile = "butterflynet.pi"
-const GenesisFile = "butterflynet.car"
+const GenesisFile = "butterflynet.car.zst"
 
 const UpgradeBreezeHeight = -1
 const BreezeGasTampingDuration = 120
diff --git a/build/buildconstants/params_calibnet.go b/build/buildconstants/params_calibnet.go
index ee6cbbb168c..65603274854 100644
--- a/build/buildconstants/params_calibnet.go
+++ b/build/buildconstants/params_calibnet.go
@@ -26,7 +26,7 @@ var NetworkBundle = "calibrationnet"
 var ActorDebugging = false
 
 const BootstrappersFile = "calibnet.pi"
-const GenesisFile = "calibnet.car"
+const GenesisFile = "calibnet.car.zst"
 
 const UpgradeBreezeHeight = -1
 const BreezeGasTampingDuration = 120
diff --git a/build/buildconstants/params_interop.go b/build/buildconstants/params_interop.go
index 91245dbe669..d45e8ef3532 100644
--- a/build/buildconstants/params_interop.go
+++ b/build/buildconstants/params_interop.go
@@ -19,7 +19,7 @@ var NetworkBundle = "caterpillarnet"
 var ActorDebugging = false
 
 const BootstrappersFile = "interopnet.pi"
-const GenesisFile = "interopnet.car"
+const GenesisFile = "interopnet.car.zst"
 
 const GenesisNetworkVersion = network.Version22
 
diff --git a/build/buildconstants/params_mainnet.go b/build/buildconstants/params_mainnet.go
index 2f61cad511f..3486279dba2 100644
--- a/build/buildconstants/params_mainnet.go
+++ b/build/buildconstants/params_mainnet.go
@@ -30,7 +30,7 @@ const ActorDebugging = false
 const GenesisNetworkVersion = network.Version0
 
 const BootstrappersFile = "mainnet.pi"
-const GenesisFile = "mainnet.car"
+const GenesisFile = "mainnet.car.zst"
 
 const UpgradeBreezeHeight abi.ChainEpoch = 41280
 
diff --git a/build/genesis.go b/build/genesis.go
index 43a1dba3d80..b32bef6d755 100644
--- a/build/genesis.go
+++ b/build/genesis.go
@@ -2,9 +2,11 @@ package build
 
 import (
 	"embed"
+	"io"
 	"path"
 
 	logging "github.com/ipfs/go-log/v2"
+	"github.com/klauspost/compress/zstd"
 
 	"github.com/filecoin-project/lotus/build/buildconstants"
 )
@@ -12,14 +14,29 @@ import (
 // moved from now-defunct build/paramfetch.go
 var log = logging.Logger("build")
 
-//go:embed genesis
-var genesisfs embed.FS
+//go:embed genesis/*.car.zst
+var genesisCars embed.FS
 
 func MaybeGenesis() []byte {
-	genBytes, err := genesisfs.ReadFile(path.Join("genesis", buildconstants.GenesisFile))
+	file, err := genesisCars.Open(path.Join("genesis", buildconstants.GenesisFile))
 	if err != nil {
-		log.Warnf("loading built-in genesis: %s", err)
+		log.Warnf("opening built-in genesis: %s", err)
 		return nil
 	}
-	return genBytes
+	defer file.Close() //nolint
+
+	decoder, err := zstd.NewReader(file)
+	if err != nil {
+		log.Warnf("creating zstd decoder: %s", err)
+		return nil
+	}
+	defer decoder.Close() //nolint
+
+	decompressedBytes, err := io.ReadAll(decoder)
+	if err != nil {
+		log.Warnf("reading decompressed genesis file: %s", err)
+		return nil
+	}
+
+	return decompressedBytes
 }
diff --git a/build/genesis/butterflynet.car b/build/genesis/butterflynet.car
deleted file mode 100644
index 910e7629156..00000000000
Binary files a/build/genesis/butterflynet.car and /dev/null differ
diff --git a/build/genesis/butterflynet.car.zst b/build/genesis/butterflynet.car.zst
new file mode 100644
index 00000000000..db55bd8cc47
Binary files /dev/null and b/build/genesis/butterflynet.car.zst differ
diff --git a/build/genesis/calibnet.car b/build/genesis/calibnet.car
deleted file mode 100644
index 775cdf7907e..00000000000
Binary files a/build/genesis/calibnet.car and /dev/null differ
diff --git a/build/genesis/calibnet.car.zst b/build/genesis/calibnet.car.zst
new file mode 100644
index 00000000000..06dad61bb4b
Binary files /dev/null and b/build/genesis/calibnet.car.zst differ
diff --git a/build/genesis/interopnet.car b/build/genesis/interopnet.car
deleted file mode 100644
index 2dadae61eb3..00000000000
Binary files a/build/genesis/interopnet.car and /dev/null differ
diff --git a/build/genesis/interopnet.car.zst b/build/genesis/interopnet.car.zst
new file mode 100644
index 00000000000..6acd1263a4a
Binary files /dev/null and b/build/genesis/interopnet.car.zst differ
diff --git a/build/genesis/mainnet.car b/build/genesis/mainnet.car
deleted file mode 100644
index f1b3f342a6c..00000000000
Binary files a/build/genesis/mainnet.car and /dev/null differ
diff --git a/build/genesis/mainnet.car.zst b/build/genesis/mainnet.car.zst
new file mode 100644
index 00000000000..cd64349e297
Binary files /dev/null and b/build/genesis/mainnet.car.zst differ