diff --git a/src/kernel/libroot/posix/glibc/libio/stdfiles.c b/src/kernel/libroot/posix/glibc/libio/stdfiles.c
index 979e92c9d6..d74fa1c412 100644
--- a/src/kernel/libroot/posix/glibc/libio/stdfiles.c
+++ b/src/kernel/libroot/posix/glibc/libio/stdfiles.c
@@ -70,9 +70,10 @@
 #endif
 
 // ToDo: stdin/stdout were originally buffered
-DEF_STDFILE(_IO_2_1_stdin_, 0, 0, _IO_NO_WRITES | _IO_UNBUFFERED);
-DEF_STDFILE(_IO_2_1_stdout_, 1, &_IO_2_1_stdin_, _IO_NO_READS | _IO_UNBUFFERED);
-DEF_STDFILE(_IO_2_1_stderr_, 2, &_IO_2_1_stdout_, _IO_NO_READS |_IO_UNBUFFERED);
+// (and probably automatically switched to unbuffered for TTYs)
+DEF_STDFILE(_IO_2_1_stdin_, 0, 0, _IO_NO_WRITES + _IO_UNBUFFERED);
+DEF_STDFILE(_IO_2_1_stdout_, 1, &_IO_2_1_stdin_, _IO_NO_READS + _IO_UNBUFFERED);
+DEF_STDFILE(_IO_2_1_stderr_, 2, &_IO_2_1_stdout_, _IO_NO_READS + _IO_UNBUFFERED);
 
 struct _IO_FILE_plus *_IO_list_all = &_IO_2_1_stderr_;
 INTVARDEF(_IO_list_all)