diff --git a/build-go.sh b/build-go.sh
index 46a767c..38f7cfa 100755
--- a/build-go.sh
+++ b/build-go.sh
@@ -19,7 +19,7 @@ v19_bootstrap="${install_dir}/bootstrap-${v19}"
 tgz19="${v19}.tar.gz"
 path_v19="${install_dir}/${tgz19}"
 
-v="${1-1.20.2}"
+v="${1-1.21.0}"
 case "${v}" in
   1.16.7) new_sum="07502f16366fbc697b1b09b842d29116e6d6607c9dc42b1d7c54b96f528c7952";;
   1.17.1) new_sum="670ce36e100669f9be572a1603858ce4a64eb4b21a31fa5cdefb778609c40337";;
@@ -38,6 +38,7 @@ case "${v}" in
   1.19.7) new_sum="1fe106fce9342c2a7ceeb04477341457cc9f0a3c07b9f2a993af09d654307f56";;
   1.20.1) new_sum="5db737840a740457c1b4b73b90dad6daa57af0da420f3ea51c39a1a81abbcc41";;
   1.20.2) new_sum="176969bb14216dd45121e46d5d0f63d339edb9042d1389d485fb6b21ee172388";;
+  1.21.0) new_sum="cf1d9b0504983c1a4c044856c389555070fbc58c3ce1703193a2c3ffe877a8b9";;
   *) errx "no hash found for version ${v}";;
 esac
 [[ "${v}" =~ 1\.2* ]] && v1_20=1 || v1_20=0
@@ -65,7 +66,7 @@ fi
 
 if [[ ! -d "${new_dir}" ]]; then
   curl -sSL "${url}/${tgznew}" >${path_new}
-  [[ -z "${new_sum}" ]] && { sha256sum ${path_new}|cut -d" " -f1; exit 0; }
+  [[ -z "${new_sum}" ]] && { echo "hashsum for version ${new}:"; sha256sum ${path_new}|cut -d" " -f1; exit 0; }
   [[ "$(sha256sum ${path_new}|cut -d" " -f1)" != "${new_sum}" ]] && errx "wrong checksum: ${path_new}"
   tar xfz ${path_new} -C ${install_dir}
 fi