diff --git a/platform/posix/btstack_uart_block_posix.c b/platform/posix/btstack_uart_block_posix.c
index 15bad3eb3..6697207ad 100644
--- a/platform/posix/btstack_uart_block_posix.c
+++ b/platform/posix/btstack_uart_block_posix.c
@@ -261,6 +261,9 @@ static int btstack_uart_posix_open(void){
         perror("posix_open: Couldn't set term attributes");
         return -1;
     }
+
+    // store fd in data source
+    transport_data_source.fd = fd;
     
     // also set baudrate
     if (btstack_uart_posix_set_baudrate(baudrate) < 0){