Update some documentation

Sec42 · Sec42 · commit 975f574099bb · 2015-07-21T22:15:40.000+02:00
diff --git a/doc/build.md b/doc/build.md
@@ -42,7 +42,6 @@ make
 Prerequisite: rad1o is connected to USB
 
 ```
-cd feldtest
 sudo make flash
 ```
 
@@ -75,6 +74,5 @@ Get the firmware, compile and flash it.
 git clone https://github.com/rad1o/f1rmware.git
 cd f1rmware/
 make
-cd feldtest
 make flash
 ```
diff --git a/doc/debugging.md b/doc/debugging.md
@@ -17,3 +17,6 @@ There is no easy way to debug the code while it runs on the board, but the board
     TOGGLE(LED2);
     TOGGLE(LED3);
     TOGGLE(LED4);
+
+## USB serial
+You can use usb serial to output text while running. Check testapp/cdc.c for a rudimentary example
