diff --git a/Firmware/README.md b/Firmware/README.md
index 1a3d1a92..18feb9cd 100644
--- a/Firmware/README.md
+++ b/Firmware/README.md
@@ -29,9 +29,7 @@ In this section we will set the compile-time parameters, later we will also set
 
 To customize the compile time parameters, copy or rename the file `tup.config.default` to `tup.config` and edit the parameters in that file:
 
-__CONFIG_BOARD_VERSION__: The board version you're using. Can be `v3.1`, `v3.2`, `v3.3` or `v3.4`.
-
-__CONFIG_48V__: Set to `y` if you're using a 48V version of the ODrive. Otherwise set to `n`. All ODrives v3.3 or older are 24V. All ODrives v3.4 or newer have a label that says 24V or 48V.
+__CONFIG_BOARD_VERSION__: The board version you're using. Can be `v3.1`, `v3.2`, `v3.3`, `v3.4-24V` or `v3.4-48V`. Check for a label on the upper side of the ODrive to find out which version you have.
 
 __CONFIG_USB_PROTOCOL__: Defines which protocol the ODrive should use on the USB interface.
  * `native`: The native ODrive protocol. Use this if you want to use the python tools in this repo.
diff --git a/Firmware/Tupfile.lua b/Firmware/Tupfile.lua
index c6423482..e9500aba 100644
--- a/Firmware/Tupfile.lua
+++ b/Firmware/Tupfile.lua
@@ -3,31 +3,33 @@ tup.include('build.lua')
 
 -- Switch between board versions
 boardversion = tup.getconfig("BOARD_VERSION")
-if boardversion == "" then boardversion = "v3.4" end
 if boardversion == "v3.1" then
     boarddir = 'Board/v3.3' -- currently all platform code is in the same v3.3 directory
     FLAGS += "-DHW_VERSION_MAJOR=3 -DHW_VERSION_MINOR=1"
+    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=false"
 elseif boardversion == "v3.2" then
     boarddir = 'Board/v3.3'
     FLAGS += "-DHW_VERSION_MAJOR=3 -DHW_VERSION_MINOR=2"
+    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=false"
 elseif boardversion == "v3.3" then
     boarddir = 'Board/v3.3'
     FLAGS += "-DHW_VERSION_MAJOR=3 -DHW_VERSION_MINOR=3"
-elseif boardversion == "v3.4" then
+    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=false"
+elseif boardversion == "v3.4-24V" then
     boarddir = 'Board/v3.3'
     FLAGS += "-DHW_VERSION_MAJOR=3 -DHW_VERSION_MINOR=4"
+    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=false"
+elseif boardversion == "v3.4-48V" then
+    boarddir = 'Board/v3.3'
+    FLAGS += "-DHW_VERSION_MAJOR=3 -DHW_VERSION_MINOR=4"
+    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=true"
+elseif boardversion == "" then
+    error("board version not specified - take a look at tup.config.default")
 else
     error("unknown board version "..boardversion)
 end
 buildsuffix = boardversion
 
--- 48V voltage version
-if tup.getconfig("48V") == "y" then
-    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=true"
-else
-    FLAGS += "-DHW_VERSION_HIGH_VOLTAGE=false"
-end
-
 -- USB I/O settings
 if tup.getconfig("USB_PROTOCOL") == "native" or tup.getconfig("USB_PROTOCOL") == "" then
     FLAGS += "-DUSB_PROTOCOL_NATIVE"
diff --git a/tup.config.default b/tup.config.default
index 5795105e..831e3b67 100644
--- a/tup.config.default
+++ b/tup.config.default
@@ -1,6 +1,6 @@
+# Copy this file to tup.config and adapt it to your needs
 CONFIG_DEBUG=y
-CONFIG_BOARD_VERSION=v3.3
-CONFIG_BOARD_48V=n
+#CONFIG_BOARD_VERSION=v3.3 # make sure this fits your board
 CONFIG_USB_PROTOCOL=native
 CONFIG_UART_PROTOCOL=ascii
 CONFIG_STEP_DIR=n