diff --git a/misc/api.func b/misc/api.func
index fe01924c8..55a4d6889 100644
--- a/misc/api.func
+++ b/misc/api.func
@@ -323,15 +323,30 @@ EOF
 # - Never blocks or fails script execution
 # ------------------------------------------------------------------------------
 post_update_to_api() {
+  # DEBUG: Show function entry
+  echo "[DEBUG] post_update_to_api() called with status=$1 exit_code=$2" >&2
+
   # Silent fail - telemetry should never break scripts
-  command -v curl &>/dev/null || return 0
+  command -v curl &>/dev/null || {
+    echo "[DEBUG] curl not found, skipping" >&2
+    return 0
+  }
 
   # Prevent duplicate submissions
   POST_UPDATE_DONE=${POST_UPDATE_DONE:-false}
-  [[ "$POST_UPDATE_DONE" == "true" ]] && return 0
+  [[ "$POST_UPDATE_DONE" == "true" ]] && {
+    echo "[DEBUG] Already sent update, skipping" >&2
+    return 0
+  }
 
-  [[ "${DIAGNOSTICS:-no}" == "no" ]] && return 0
-  [[ -z "${RANDOM_UUID:-}" ]] && return 0
+  [[ "${DIAGNOSTICS:-no}" == "no" ]] && {
+    echo "[DEBUG] DIAGNOSTICS=no, skipping" >&2
+    return 0
+  }
+  [[ -z "${RANDOM_UUID:-}" ]] && {
+    echo "[DEBUG] RANDOM_UUID empty, skipping" >&2
+    return 0
+  }
 
   local status="${1:-failed}"
   local raw_exit_code="${2:-1}"
@@ -377,10 +392,16 @@ post_update_to_api() {
 EOF
   )
 
+  echo "[DEBUG] Sending update to: $TELEMETRY_URL" >&2
+  echo "[DEBUG] Update payload: $JSON_PAYLOAD" >&2
+
   # Fire-and-forget: never block, never fail
-  curl -fsS -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
+  local http_code
+  http_code=$(curl -sS -w "%{http_code}" -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
     -H "Content-Type: application/json" \
-    -d "$JSON_PAYLOAD" &>/dev/null || true
+    -d "$JSON_PAYLOAD" -o /dev/stderr 2>&1) || true
+
+  echo "[DEBUG] HTTP response code: $http_code" >&2
 
   POST_UPDATE_DONE=true
 }
diff --git a/misc/build.func b/misc/build.func
index c719e1fdb..6649b7e3d 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -1882,7 +1882,7 @@ advanced_settings() {
       fi
       ;;
 
-    # ══════════════���════════════════════════════════════════════════════════════
+    # ══════════════����════════════════════════════════════════════════════════════
     # STEP 3: Container ID
     # ═══════════════════════════════════════════════════════════════════════════
     3)
@@ -4014,6 +4014,9 @@ EOF'
   if [[ $install_exit_code -ne 0 ]]; then
     msg_error "Installation failed in container ${CTID} (exit code: ${install_exit_code})"
 
+    # Report failure to telemetry API
+    post_update_to_api "failed" "$install_exit_code"
+
     # Copy both logs from container before potential deletion
     local build_log_copied=false
     local install_log_copied=false