diff --git a/run b/run
index 9f92df5..4f79b1a 100755
--- a/run
+++ b/run
@@ -648,6 +648,63 @@ step27() {
   }
 }
 
+# commit a4d1edac8d65e1aa4b565f6fb11ab78541d97efa
+# Author: Eric Joldasov <bratishkaerik@getgoogleoff.me>
+# Date:   2023-06-15T10:43:59+03:00
+#
+#     stage1: update zig1.wasm after renaming "@XtoY" to "YfromX"
+#
+STEP28=a4d1edac8d65e1aa4b565f6fb11ab78541d97efa
+STEP28_=0.10.0-3728-ga4d1edac8d
+step28() {
+  rm -fr "../zig-$STEP28_"
+  git archive --prefix=zig-$STEP28_/ $STEP28 | tar -C .. -x
+  {
+    pushd "../zig-$STEP28_"
+    cp ../zig-$STEP27_/stage1/zig1.wasm stage1/zig1.wasm
+    halfbuild 16
+    build/zig2 build update-zig1
+    popd
+  }
+}
+
+# commit 21ac0beb436f49fe49c6982a872f2dc48e4bea5e
+# Author: Matthew Lugg <mlugg@mlugg.co.uk>
+# Date:   2023-06-23T21:55:31+03:00
+#
+#     update zig1.wasm
+#
+#     Needed due to the breaking changes to casting builtins, which are used
+#     by the compiler when building itself.
+#
+#STEP28_A=21ac0beb436f49fe49c6982a872f2dc48e4bea5e
+#STEP28_=0.10.0-3813-g21ac0beb43
+
+# One commit before changing cast builtin syntax:
+#
+# commit 447ca4e3fff021f471b748187b53f0a4744ad0bc
+# Author: Matthew Lugg <mlugg@mlugg.co.uk>
+# Date:   2023-06-23T00:40:13+03:00
+#
+#     translate-c: update to new cast builtin syntax
+#
+#STEP28_B=447ca4e3fff021f471b748187b53f0a4744ad0bc
+#step28() {
+#  rm -fr "../zig-$STEP28_"
+#  git archive --prefix=zig-$STEP28_/ $STEP28_A | tar -C .. -x
+#  mv ../zig-$STEP28_/lib ../zig-$STEP28_/lib.bk
+#  git archive --prefix=zig-$STEP28_/ $STEP28_B lib | tar -C .. -x
+#  {
+#    pushd "../zig-$STEP28_"
+#    cp ../zig-$STEP27_/stage1/zig1.wasm stage1/zig1.wasm
+#    halfbuild 16
+#    rm -fr lib
+#    mv lib.bk lib
+#    build/zig2 build update-zig1
+#    popd
+#  }
+#}
+
 if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
   set -xeuo pipefail
   step=${1:-step00}
@@ -682,4 +739,5 @@ if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
   if [[ "$step" -le 25 ]]; then step25; fi
   if [[ "$step" -le 26 ]]; then step26; fi
   if [[ "$step" -le 27 ]]; then step27; fi
+  if [[ "$step" -le 28 ]]; then step28; fi
 fi