diff --git a/.github/workflows/build-deb.yaml b/.github/workflows/build-deb.yaml
index 9fca60701..f8de199f6 100644
--- a/.github/workflows/build-deb.yaml
+++ b/.github/workflows/build-deb.yaml
@@ -87,12 +87,12 @@ jobs:
             base_ref=$(git log --root --reverse -n1 --format=%H)
           fi
 
-          modified_files_json=$(git diff --name-only ${base_ref} HEAD | \
+          modified_files=$(git diff --name-only ${base_ref} HEAD | \
             while read line; do
               jq -n --arg path "$line" '$path'
-            done | jq -n '. |= [inputs]')
+            done | jq -n '. |= [inputs]' | jq '.| tostring')
 
-          echo "modified_files=${{ fromJSON(${modified_files_json}) }}" >> "${GITHUB_OUTPUT}"
+          echo "modified_files=${modified_files}) >> "${GITHUB_OUTPUT}"
 
 
   run-job: