diff --git a/Makefile b/Makefile
index 67cd872f3..e74d79b4d 100644
--- a/Makefile
+++ b/Makefile
@@ -83,9 +83,8 @@ proto-all: proto-gen proto-lint proto-check-breaking
 .PHONY: proto-all
 
 proto-gen:
-	@docker pull -q tendermintdev/docker-build-proto
 	@echo "Generating Protobuf files"
-	@docker run -v $(shell pwd):/workspace --workdir /workspace tendermintdev/docker-build-proto sh ./scripts/protocgen.sh
+	@$(DOCKER_PROTO_BUILDER) sh ./scripts/protocgen.sh
 .PHONY: proto-gen
 
 proto-lint:
diff --git a/scripts/protocgen.sh b/scripts/protocgen.sh
index b6d35ac66..6f5662a78 100755
--- a/scripts/protocgen.sh
+++ b/scripts/protocgen.sh
@@ -4,13 +4,10 @@ set -euo pipefail
 # By default, this script runs against the latest commit to the master branch
 # in the Tendermint spec repository. To use this script with a different version
 # of the spec repository, run it with the $VERS environment variable set to the
-# desired commit in the spec repo.
+# desired branch name or commit hash from the spec repo.
 
 : ${VERS:=master}
 URL_PATH=tarball/
-if [[ VERS -ne master ]]; then
-    URL_PATH=tarball/refs/tags/v
-fi
 
 echo "fetching proto files"
 
@@ -18,10 +15,13 @@ echo "fetching proto files"
 REF=$(curl -H "Accept: application/vnd.github.v3.sha" -qL \
   "https://api.github.com/repos/tendermint/spec/commits/${VERS}" \
   | cut -c -7)
-curl -qL "https://api.github.com/repos/tendermint/spec/${URL_PATH}${REF}" | tar -xzf - tendermint-spec-"$REF"/
 
-cp -r ./tendermint-spec-"$REF"/proto/tendermint/* ./proto/tendermint
-cp -r ./tendermint-spec-"$REF"/third_party/** ./third_party
+readonly OUTDIR="tendermint-spec-${REF}"
+curl -qL "https://api.github.com/repos/tendermint/spec/${URL_PATH}${REF}" | tar -xzf - ${OUTDIR}/
+
+
+cp -r ${OUTDIR}/proto/tendermint/* ./proto/tendermint
+cp -r ${OUTDIR}/third_party/** ./third_party
 
 MODNAME="$(go list -m)"
 find ./proto/tendermint -name '*.proto' -not -path "./proto/tendermint/abci/types.proto" \
@@ -31,7 +31,7 @@ find ./proto/tendermint -name '*.proto' -not -path "./proto/tendermint/abci/type
 # so that it can be moved into the ./abci/types directory.
 sh ./scripts/protopackage.sh ./proto/tendermint/abci/types.proto $MODNAME "abci/types"
 
-buf generate --path proto/tendermint --template ./tendermint-spec-"$REF"/proto/buf.gen.yaml --config ./tendermint-spec-"$REF"/proto/buf.yaml
+buf generate --path proto/tendermint --template ./${OUTDIR}/proto/buf.gen.yaml --config ./${OUTDIR}/proto/buf.yaml
 
 mv ./proto/tendermint/abci/types.pb.go ./abci/types
 
@@ -39,8 +39,8 @@ echo "proto files have been compiled"
 
 echo "removing copied files"
 
-find ./tendermint-spec-"$REF"/proto/tendermint/ -name *.proto \
-	| sed "s/\.\/tendermint-spec-$REF\/\(.*\)/\1/g" \
+find ${OUTDIR}/proto/tendermint/ -name *.proto \
+	| sed "s/\.\/$OUTDIR\/\(.*\)/\1/g" \
 	| xargs -I {} rm {}
 
-rm -rf ./tendermint-spec-"$REF"
+rm -rf ${OUTDIR}