diff --git a/.github/workflows/ifx_package_core.yml b/.github/workflows/ifx_package_core.yml
index 2f1b64814..db7ac5fe5 100644
--- a/.github/workflows/ifx_package_core.yml
+++ b/.github/workflows/ifx_package_core.yml
@@ -91,10 +91,13 @@ jobs:
           # Set up basic environment for later steps
           CORE_VER=$(extra/get_core_version.sh)
           ALL_BOARD_DATA=$(extra/get_board_details.sh | jq -c 'sort_by(.variant)')
-          if [[ "${{ github.event_name }}" == "push" ]]; then
-            # limit direct pushes to this board family's own boards; PRs still
-            # validate the full board matrix before merge
-            ALL_BOARD_DATA=$(jq -c 'map(select(.feature_board == true))' <<< "${ALL_BOARD_DATA}")
+          # limit builds/tests to this board family's own boards, for both
+          # direct pushes and PRs. Only apply the filter if it leaves at
+          # least one board, so branches with no feature_board opted in yet
+          # keep building the full board set.
+          FEATURE_BOARD_DATA=$(jq -c 'map(select(.feature_board == true))' <<< "${ALL_BOARD_DATA}")
+          if [[ "$(jq 'length' <<< "${FEATURE_BOARD_DATA}")" -gt 0 ]]; then
+            ALL_BOARD_DATA="${FEATURE_BOARD_DATA}"
           fi
           echo "CORE_HASH=$(git describe --always $HEAD_REF)" >> "$GITHUB_ENV"
           echo "ALL_BOARD_DATA=${ALL_BOARD_DATA}" >> "$GITHUB_ENV"