diff --git a/install-wings.sh b/install-wings.sh
index 7e4c922..9828f1d 100644
--- a/install-wings.sh
+++ b/install-wings.sh
@@ -34,9 +34,19 @@ need_tty() {
 
 prompt() {
   local msg="$1"
-  local out
+  local out line
   printf "${BOLD}%s${RESET}" "$msg" >"$TTY"
   IFS= read -r out <"$TTY"
+
+  # A pasted value (e.g. join-data copied from the panel UI) can arrive with an
+  # embedded newline. `read` stops at the first one, which would otherwise
+  # silently truncate the rest onto a "phantom" line consumed by a later
+  # prompt. Drain any additional lines that are already buffered so nothing
+  # gets lost; this never blocks waiting on new keystrokes.
+  while IFS= read -r -t 0.1 line <"$TTY" 2>/dev/null; do
+    out+="$line"
+  done
+
   printf "%s" "$out"
 }