diff --git a/doc/advanced-install.md b/doc/advanced-install.md
index 8976041..0fee0a3 100644
--- a/doc/advanced-install.md
+++ b/doc/advanced-install.md
@@ -11,8 +11,8 @@ Then compile and upload the sketch.
 
 ## Works with no source code changes
 
-* Seeeduino Xiao
-* Adafruit Qt Py
+* Seeeduino Xiao SAMD21
+* Adafruit Qt Py SAMD21
 
 ## Known to work with source code changes
 
@@ -24,6 +24,18 @@ Then compile and upload the sketch.
 * Adafruit GEMMA M0
 * Adafruit Feather M0
 
+## Will Not Work!
+
+The RP2040 chip will not work, because it lacks a USB MCU,
+needed by the MIDIUSB library. 
+I'm listing specific devices here
+in the hopes that seeing them crossed out will prevent people from
+making a purchasing mistake!
+
+* ~~Seeeduino Xiao RP2040~~ Will not work!
+* ~~Adafruit Qt Pi RP2040~~ Will not work!
+* ~~Any RP2040 Device~~ Will not work!
+
 
 # Advanced Wiring
 
diff --git a/doc/easy-install.md b/doc/easy-install.md
index 5202c37..213a9d1 100644
--- a/doc/easy-install.md
+++ b/doc/easy-install.md
@@ -1,10 +1,10 @@
 # Easy Installation
 
-1. Get a Seeeduino XIAO
-2. Download the most recent xiao firmware from
+1. Get a Seeeduino XIAO SAMD21
+2. Download the most recent XIAO SAMD21 firmware from
 [releases](https://github.com/nealey/vail-adapter/releases)
 3. [Enter bootloader mode](https://wiki.seeedstudio.com/Seeeduino-XIAO/#enter-bootloader-mode)
-4. Copy the firmware onto the XIAO
+4. Copy the firmware onto the XIAO SAMD21
 
 [Wideo walkthrough of firmware upload](https://www.youtube.com/watch?v=IgOdkUe5SMY) (3:07)