diff --git a/.github/workflows/manual-deploy-obscuro-gateway.yml b/.github/workflows/manual-deploy-obscuro-gateway.yml
index 8afa56f478..a1c84ca962 100644
--- a/.github/workflows/manual-deploy-obscuro-gateway.yml
+++ b/.github/workflows/manual-deploy-obscuro-gateway.yml
@@ -43,7 +43,7 @@ jobs:
       - name: 'Set up environment variables'
         id: setup_env
         run: |
-          INSTANCE_PREFIX="${{ github.event.inputs.instance_type == 'primary' && '' || format('{}-', github.event.inputs.instance_type) | toUpper }}"
+          INSTANCE_PREFIX=$(echo "${{ github.event.inputs.instance_type == 'primary' && '' || format('{}-', github.event.inputs.instance_type) }}" | tr '[:lower:]' '[:upper:]')
           INSTANCE_SUFFIX="${{ github.event.inputs.instance_type == 'primary' && '' || format('-{}', github.event.inputs.instance_type) }}"
           
           echo "INSTANCE_SUFFIX=$INSTANCE_SUFFIX" >> $GITHUB_ENV