diff --git a/examples/stm32/f1/lisa-m/usb_cdcacm/cdcacm_test.py b/examples/stm32/f1/lisa-m/usb_cdcacm/cdcacm_test.py
index 02c458ca..bf1bef36 100644
--- a/examples/stm32/f1/lisa-m/usb_cdcacm/cdcacm_test.py
+++ b/examples/stm32/f1/lisa-m/usb_cdcacm/cdcacm_test.py
@@ -24,7 +24,7 @@ while 1==1:
 
     ser.write("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*(){}");
 
-    buf = ser.read(75);
+    buf = ser.read(1024);
 
     cycles += 1