diff --git a/firmware/LICENSE-samd20-gcc-blackmagic.md b/firmware/LICENSE-samd20-gcc-blackmagic.md
index 31ec518..e12c7a8 100644
--- a/firmware/LICENSE-samd20-gcc-blackmagic.md
+++ b/firmware/LICENSE-samd20-gcc-blackmagic.md
@@ -1,5 +1,5 @@
 Much of the source code in this project is licensed by ARM or Atmel
-wuth a modified 3-clause BSD license. See file headers for more details.
+with a modified 3-clause BSD license. See file headers for more details.
 
 Everything else is under a
 [MIT License](http://opensource.org/licenses/MIT) as follows:
diff --git a/firmware/Makefile b/firmware/Makefile
index e735633..12b92f4 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -1,4 +1,4 @@
-# Compiles firmware written in C and assembler for the nRF51
+# Compiles firmware written in C and assembler for the Atmel SAM D20
 # Copyright (C) 2014
 #
 # Permission is hereby granted, free of charge, to any person obtaining
@@ -214,7 +214,7 @@ gdbscript: Makefile config.mk
 	@$(ECHO) "file $(TARGET).elf" >> gdbscript
 ifdef BLACKMAGIC_PATH
 	@$(ECHO) "# Connect to a specified blackmagic" >> gdbscript
-	@$(ECHO) "target external-remote $(BLACKMAGIC_PATH)" >> gdbscript
+	@$(ECHO) "target extended-remote $(BLACKMAGIC_PATH)" >> gdbscript
 endif
 
 # Prints a list of symlinks to a device
@@ -248,4 +248,4 @@ emacs:
 clean:
 	$(RM) $(OUTPUT_PATH)*
 	$(RM) gdbscript
-	$(RM) TAGS
\ No newline at end of file
+	$(RM) TAGS
diff --git a/firmware/README-samd20-gcc-blackmagic.md b/firmware/README-samd20-gcc-blackmagic.md
index 04ef995..81594fb 100644
--- a/firmware/README-samd20-gcc-blackmagic.md
+++ b/firmware/README-samd20-gcc-blackmagic.md
@@ -20,6 +20,22 @@ sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
 sudo apt-get update && sudo apt-get install gcc-arm-none-eabi
 ```
 
+###### Note about gcc-arm-embedded on Ubuntu 14.04 and later
+
+If you are using Ubuntu 14.04 and later, please be careful because
+there are packages with same name but produced by Debian and inherited
+by Ubuntu. Simply follow the above 3 steps, you may end up with
+gcc-arm-none-eabi from Ubuntu. So to install gcc-arm-none-eabi from
+ARM, steps are:
+
+```
+1). sudo apt-get remove binutils-arm-none-eabi gcc-arm-none-eabi
+2). sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
+3). sudo apt-get update
+4). sudo apt-get install gcc-arm-none-eabi=4-8-2014q2-0trusty10
+```
+Meanwhile we are working with Debian to consolidate and unify this toolchain.
+
 ## Usage ##
 
 ### Project Options ###
diff --git a/firmware/chip/sections.ld b/firmware/chip/sections.ld
index 8dcdb7d..8318102 100644
--- a/firmware/chip/sections.ld
+++ b/firmware/chip/sections.ld
@@ -44,7 +44,9 @@
  *   __data_start
  *   __data_end
  *   __bss_start
+ *   __bss_start__
  *   __bss_end
+ *   __bss_end__
  *   __end__
  *   end
  *   __heap_start
@@ -134,10 +136,12 @@ SECTIONS
 	{
 		. = ALIGN(4);
 		__bss_start = .;
+		__bss_start__ = __bss_start;
 		*(.bss .bss.*)
 		*(COMMON)
 		. = ALIGN(4);
 		__bss_end = .;
+		__bss_end__ = __bss_end;
 	} > RAM
 
 	.heap (COPY):