diff --git a/go/build.sh b/go/build.sh
index 6aad819..d4f9f63 100755
--- a/go/build.sh
+++ b/go/build.sh
@@ -4,4 +4,5 @@ set -eu
 export MAKEFLAGS="-j${NPROC:-$(nproc)}"
 
 [ ! -d build/install-bootstrap ] && ./build_bootstrap.sh
+[ ! -d build/install-go19 ] && ./build_go19.sh
 [ ! -d build/install-go ] && ./build_go.sh
diff --git a/go/build_bootstrap.sh b/go/build_bootstrap.sh
index 0877571..b38effb 100755
--- a/go/build_bootstrap.sh
+++ b/go/build_bootstrap.sh
@@ -14,10 +14,18 @@ cd "go1.4-bootstrap-$version_bootstrap"
 
 # Build and install
 (cd src; ./make.bash)
-rm -rf pkg/obj src/cmd src/internal src/builtin
-find src -type f \( ! -name "*.go" \) -delete
-find src -type f \( -name "*_test.go" -o -name "*_test_*.go" \) -delete
-find src -type d -name "testdata" -exec rm -r {} +
-find src -type d -empty -delete
+
+find src -type f \( ! -name '*.go' \
+    -a ! -name '*.c' \
+    -a ! -name '*.h' \
+    -a ! -name '*.s' \
+    -a ! -name '*.S' \
+    -a ! -name 'p256_asm_table.bin' \
+\) -print -delete
+find src -type f -name '*_test.go' -print -delete
+find src -type d -empty -print -delete
+find pkg -type f -name '*.a' -print -delete
+find pkg -type d -empty -print -delete
+
 mkdir -p "$dir_install"
 cp -at "$dir_install" bin pkg src
diff --git a/go/build_go.sh b/go/build_go.sh
index 854724f..e8852bd 100755
--- a/go/build_go.sh
+++ b/go/build_go.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 set -eu
 
-version_go=1.15
+version_go=1.21.0
 
 dir_download="$PWD/download"
 mkdir -p build; cd build
@@ -13,11 +13,19 @@ tar xf "$dir_download/go$version_go.src.tar.gz" -C "go$version_go" --strip-compo
 cd "go$version_go"
 
 # Build and install
-(cd src; GOROOT_BOOTSTRAP="$PWD/../../install-bootstrap" ./make.bash)
-rm -rf pkg/obj src/cmd src/builtin
-find src -type f \( ! -name "*.go" -a ! -name "*.s" -a ! -name "*.h" \) -delete
-find src -type f \( -name "*_test.go" -o -name "*_test_*.go" \) -delete
-find src -type d -name "testdata" -exec rm -r {} +
-find src -type d -empty -delete
+(cd src; GOROOT_BOOTSTRAP="$PWD/../../install-go19" ./make.bash)
+
+find src -type f \( ! -name '*.go' \
+    -a ! -name '*.c' \
+    -a ! -name '*.h' \
+    -a ! -name '*.s' \
+    -a ! -name '*.S' \
+    -a ! -name 'p256_asm_table.bin' \
+\) -print -delete
+find src -type f -name '*_test.go' -print -delete
+find src -type d -empty -print -delete
+find pkg -type f -name '*.a' -print -delete
+find pkg -type d -empty -print -delete
+
 mkdir -p "$dir_install"
 cp -at "$dir_install" bin pkg src
diff --git a/go/build_go19.sh b/go/build_go19.sh
new file mode 100755
index 0000000..b4b1849
--- /dev/null
+++ b/go/build_go19.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+set -eu
+
+version_go19=1.19.12
+
+dir_download="$PWD/download"
+mkdir -p build; cd build
+dir_install="$PWD/install-go19"
+
+# Prepare source
+mkdir -p "go$version_go19"
+tar xf "$dir_download/go$version_go19.src.tar.gz" -C "go$version_go19" --strip-components 1
+cd "go$version_go19"
+
+# Build and install
+(cd src; GOROOT_BOOTSTRAP="$PWD/../../install-bootstrap" ./make.bash)
+
+find src -type f \( ! -name '*.go' \
+    -a ! -name '*.c' \
+    -a ! -name '*.h' \
+    -a ! -name '*.s' \
+    -a ! -name '*.S' \
+    -a ! -name 'p256_asm_table.bin' \
+\) -print -delete
+find src -type f -name '*_test.go' -print -delete
+find src -type d -empty -print -delete
+find pkg -type f -name '*.a' -print -delete
+find pkg -type d -empty -print -delete
+
+mkdir -p "$dir_install"
+cp -at "$dir_install" bin pkg src
diff --git a/go/download.sh b/go/download.sh
index 315cf57..6aa858d 100755
--- a/go/download.sh
+++ b/go/download.sh
@@ -1,13 +1,15 @@
 #!/bin/sh
 set -eu
 
-version_go=1.15  # https://golang.org/dl/
+version_go=1.21.0  # https://golang.org/dl/
+version_go19=1.19.12
 version_bootstrap=20171003  # https://golang.org/doc/install/source#go14
 
 mkdir -p download
 cd download
 
 wget -c "https://dl.google.com/go/go$version_go.src.tar.gz"
+wget -c "https://dl.google.com/go/go$version_go19.src.tar.gz"
 wget -c "https://dl.google.com/go/go1.4-bootstrap-$version_bootstrap.tar.gz"
 
 sha256sum -c ../download.sha256
diff --git a/go/download.sha256 b/go/download.sha256
index cd475f3..cb8097c 100644
--- a/go/download.sha256
+++ b/go/download.sha256
@@ -1,2 +1,3 @@
-69438f7ed4f532154ffaf878f3dfd83747e7a00b70b3556eddabf7aaee28ac3a  go1.15.src.tar.gz
+ee5d50e0a7fd74ba1b137cb879609aaaef9880bf72b5d1742100e38ae72bb557  go1.19.12.src.tar.gz
+818d46ede85682dd551ad378ef37a4d247006f12ec59b5b755601d2ce114369a  go1.21.0.src.tar.gz
 f4ff5b5eb3a3cae1c993723f3eab519c5bae18866b5e5f96fe1102f0cb5c3e52  go1.4-bootstrap-20171003.tar.gz