diff --git a/boards/feather-m0/Makefile.include b/boards/feather-m0/Makefile.include
index df048f40b4..036fdb4188 100644
--- a/boards/feather-m0/Makefile.include
+++ b/boards/feather-m0/Makefile.include
@@ -1,3 +1,8 @@
+# Boards after around 2018 use the more modern UF2 bootloader.
+# Comment out for the old BOSSA bootloader or upgrade to
+# the UF2 bootloader.
+CFLAGS += -DBOOTLOADER_UF2
+
 # setup the flash tool used
 ifeq ($(PROGRAMMER),jlink)
   # in case J-Link is attached to SWD pins, use a plain CPU memory model
diff --git a/boards/feather-m0/doc.txt b/boards/feather-m0/doc.txt
index af469fe246..6becaa56f7 100644
--- a/boards/feather-m0/doc.txt
+++ b/boards/feather-m0/doc.txt
@@ -52,6 +52,14 @@ Example with `hello-world` application:
           bootloader mode by double tapping the reset button before running the
           flash command.
 
+@note     Adafruit changed the bootloader from the old BOSSA bootloader to the
+          more modern UF2 bootloader around 2018. If you have a very old board,
+          it is recommended to upgrade the bootloader to the new UF2
+          bootloader. Otherwise the bootloader has to be enabled by double
+          tapping the reset button.<br/>
+          Upgrade instructions can be found at Adafruit:
+          https://learn.adafruit.com/installing-circuitpython-on-samd21-boards/installing-the-uf2-bootloader
+
 ### Using the WiFi interface
 
 To enable the WiFi interface of the Feather M0 WiFi variant of the board