diff --git a/cmd/coordinator/status.go b/cmd/coordinator/status.go
index 827d6cdb45..cac5f00b7d 100644
--- a/cmd/coordinator/status.go
+++ b/cmd/coordinator/status.go
@@ -373,7 +373,7 @@ func newMacOSARM64Checker() *healthChecker {
 		ID:     "macos-arm64",
 		Title:  "macOS ARM64 (M1 Mac minis)",
 		DocURL: "https://golang.org/issue/39782",
-		Check:  hostTypeChecker("host-darwin-arm64-11_0-toothrot"),
+		Check:  hostTypeChecker("host-darwin-arm64-12_0-toothrot"),
 	}
 }
 
diff --git a/cmd/racebuild/racebuild.go b/cmd/racebuild/racebuild.go
index 8059525635..2ef403838b 100644
--- a/cmd/racebuild/racebuild.go
+++ b/cmd/racebuild/racebuild.go
@@ -95,7 +95,7 @@ cp llvm-project/compiler-rt/lib/tsan/go/race_darwin_amd64.syso go/src/runtime/ra
 	&Platform{
 		OS:   "darwin",
 		Arch: "arm64",
-		Type: "darwin-arm64-11_0-toothrot",
+		Type: "darwin-arm64-12_0-toothrot",
 		Script: `#!/usr/bin/env bash
 set -e
 git clone https://go.googlesource.com/go
diff --git a/cmd/release/release.go b/cmd/release/release.go
index 400555d3c4..e26ea9be2e 100644
--- a/cmd/release/release.go
+++ b/cmd/release/release.go
@@ -219,7 +219,7 @@ var builds = []*Build{
 		OS:      "darwin",
 		Arch:    "arm64",
 		Race:    true,
-		Builder: "darwin-arm64-11_0-toothrot",
+		Builder: "darwin-arm64-12_0-toothrot",
 	},
 	{
 		OS:        "linux",
diff --git a/dashboard/builders.go b/dashboard/builders.go
index 41f7292dc4..40220e81a8 100644
--- a/dashboard/builders.go
+++ b/dashboard/builders.go
@@ -40,7 +40,7 @@ var slowBotAliases = map[string]string{
 	"arm64":                "linux-arm64-aws",
 	"darwin":               "darwin-amd64-10_14",
 	"darwin-amd64":         "darwin-amd64-10_14",
-	"darwin-arm64":         "darwin-arm64-11_0-toothrot",
+	"darwin-arm64":         "darwin-arm64-12_0-toothrot",
 	"ios-arm64":            "ios-arm64-corellium",
 	"dragonfly":            "dragonfly-amd64",
 	"freebsd":              "freebsd-amd64-12_2",
@@ -496,8 +496,17 @@ var Hosts = map[string]*HostConfig{
 	},
 	"host-darwin-arm64-11_0-toothrot": &HostConfig{
 		IsReverse: true,
-		ExpectNum: 2,
 		Notes:     "macOS Big Sur (11.0) ARM64 (M1). Mac mini",
+		ExpectNum: 1,
+		env: []string{
+			"GOROOT_BOOTSTRAP=/Users/gopher/goboot",
+		},
+		SSHUsername: "gopher",
+	},
+	"host-darwin-arm64-12_0-toothrot": &HostConfig{
+		IsReverse: true,
+		ExpectNum: 1,
+		Notes:     "macOS Big Sur (12.0) ARM64 (M1). Mac mini",
 		env: []string{
 			"GOROOT_BOOTSTRAP=/Users/gopher/goboot",
 		},
@@ -2264,10 +2273,15 @@ func init() {
 		Name:           "darwin-arm64-11_0-toothrot",
 		HostType:       "host-darwin-arm64-11_0-toothrot",
 		distTestAdjust: macTestPolicy,
-		buildsRepo: func(repo, branch, goBranch string) bool {
-			// Darwin ARM64 added in Go 1.16.
-			return atLeastGo1(goBranch, 16) && defaultPlusExpBuild(repo, branch, goBranch)
-		},
+		buildsRepo:     defaultPlusExpBuild,
+	})
+	addBuilder(BuildConfig{
+		Name:           "darwin-arm64-12_0-toothrot",
+		HostType:       "host-darwin-arm64-12_0-toothrot",
+		env:            []string{"MallocNanoZone=0"}, // golang.org/issue/49138
+		KnownIssue:     49149,
+		distTestAdjust: macTestPolicy,
+		buildsRepo:     defaultPlusExpBuild,
 	})
 	addBuilder(BuildConfig{
 		Name:           "darwin-amd64-race",