diff --git a/README.md b/README.md
index ab65201..e726d2e 100644
--- a/README.md
+++ b/README.md
@@ -47,7 +47,7 @@ This firmware includes companion UIs and support for several devices; notable ex
 Flash using the MeshCore web flasher:
 
 1. Open https://flasher.meshcore.co.uk/ and choose "Custom Firmware".
-2. For first-time installation, perform a full flash erase (this removes all settings).
+2. For first-time installation (use the *-merged version), perform a full flash erase (this removes all settings). *take care*, if you upgrade the version to a newer one, use the non-merged version!
 3. Upload the built firmware image and flash to your device.
 
 Notes: