diff --git a/configs/z80sim/nshconfig b/configs/z80sim/nshconfig
index b14b0936222..63326cb6f2c 100644
--- a/configs/z80sim/nshconfig
+++ b/configs/z80sim/nshconfig
@@ -130,7 +130,7 @@ CONFIG_DISABLE_POSIX_TIMERS=y
 CONFIG_DISABLE_PTHREAD=y
 CONFIG_DISABLE_SIGNALS=n
 CONFIG_DISABLE_MQUEUE=y
-CONFIG_DISABLE_MOUNTPOINT=n
+CONFIG_DISABLE_MOUNTPOINT=y
 CONFIG_DISABLE_ENVIRON=y
 
 #
diff --git a/configs/z80sim/src/z80_serial.c b/configs/z80sim/src/z80_serial.c
index 9a8fa0f89d7..2dcd56c0531 100644
--- a/configs/z80sim/src/z80_serial.c
+++ b/configs/z80sim/src/z80_serial.c
@@ -288,7 +288,7 @@ static boolean up_txfifonotfull(struct uart_dev_s *dev)
 
 static boolean up_txfifoempty(struct uart_dev_s *dev)
 {
-  return FALSE;
+  return TRUE;
 }
 
 /****************************************************************************