diff --git a/.harness/firebase-deploy.yaml b/.harness/firebase-deploy.yaml
index dc38391..f1be302 100644
--- a/.harness/firebase-deploy.yaml
+++ b/.harness/firebase-deploy.yaml
@@ -21,7 +21,7 @@ spec:
             spec:
               name: build
               container: alpine/git
-              shell: bash
+              shell: sh
               script: >
-                bash ./deploy.firebase.sh '${{
+                sh ./deploy.firebase.sh '${{
                 secrets.get("resume-firebase-squeaky2x3-gmail-token") }}'
diff --git a/deploy.firebase.sh b/deploy.firebase.sh
index 7d6b540..4a51a02 100755
--- a/deploy.firebase.sh
+++ b/deploy.firebase.sh
@@ -1,4 +1,4 @@
-#! /bin/bash
+#! /bin/sh
 
 set -o pipefail
 set -e
@@ -8,7 +8,7 @@ if ! which firebase; then
    f="$(mktemp)"
    curl -sL https://firebase.tools > "$f"
    export upgrade=true
-   sudo bash "$f"
+   $(if tty &> /dev/null; then echo sudo; fi) sh "$f"
 fi
 
 outdir=./deploy