diff --git a/crossfire/agent.rkt b/crossfire/agent.rkt
index 36349fc..c838571 100644
--- a/crossfire/agent.rkt
+++ b/crossfire/agent.rkt
@@ -243,7 +243,7 @@
                                       (sync/timeout *subproc-kill-delay* proc)
                                       ;; exit without reporting status
                                       (kill-thread (current-thread)))])
-          (define line-match (regexp-match-evt #px"^[^\n]*\n" out))
+          (define line-match (read-bytes-line-evt out))
           (define eof-e (eof-evt out))
           (let loop ([reached-eof #f] [proc-done #f])
             (match (sync/enable-break (if proc-done never-evt proc)
@@ -255,7 +255,7 @@
               [(? eof-object?)
                (unless proc-done
                  (loop #t proc-done))]
-              [(list line)
+              [(? bytes? line)
                (define line-str (bytes->string/utf-8 line #\?))
                (define line-parts
                  (and line-str