diff --git a/lib/README b/lib/README
index 8271ae4c..f8e4d5f2 100644
--- a/lib/README
+++ b/lib/README
@@ -58,6 +58,12 @@ The bossac directory contains code from:
   https://github.com/shumatech/BOSSA
 version 1.9 (b176eeef918fc810045c832348590595120187b4).
 
+The hidflash directory contains code from:
+  https://github.com/Serasidis/STM32_HID_Bootloader
+version 2.2.2 (2ab7927a27b7b78ef730782ea5f9b5d2c8f34671). It has been
+modified to work with Klipper - see hidflash/README for the
+details. See changes.diff for the modifications.
+
 The pru_rpmsg directory contains code from:
   https://github.com/dinuxbg/pru-gcc-examples
 revision 425a42d82006cf0aa24be27b483d2f6a41607489. The code is taken