diff --git a/boards/openmote-b/doc.txt b/boards/openmote-b/doc.txt
index 89a10e23c5..b9c1d35276 100644
--- a/boards/openmote-b/doc.txt
+++ b/boards/openmote-b/doc.txt
@@ -40,6 +40,15 @@ RIOT support flashing with USB by default.
 You may have to specify the flashing port with
 `PORT_DEV=<my_openmote_port> make flash`
 
+The flash tool needs to convert the generated Hex file to RAW format.
+For this it needs to have the intelhex library installed.
+
+    apt install python3-intelhex
+
+or
+
+    pip3 install intelhex
+
 ### Flashing via JTAG
 
 To be able to flash the board via JTAG you need to install Seggers JLinkExe