diff --git a/tools/sky/msp430-bsl-linux b/tools/sky/msp430-bsl-linux
index 171320d98f0acf903b09be5660a99ae7a012bbe7..ed5ec556056da54151c275b5b2f4ea54629e7fe2 100755
--- a/tools/sky/msp430-bsl-linux
+++ b/tools/sky/msp430-bsl-linux
@@ -1625,5 +1625,5 @@ if __name__ == '__main__':
         sys.exit(1)         #set errorlevel for script usage
     except Exception, msg:  #every Exception is caught and displayed
         if DEBUG: raise     #show full trace in debug mode
-        sys.stderr.write("\nAn error occoured:\n%s\n" % msg) #short messy in user mode
+        sys.stderr.write("\nAn error occurred:\n%s\n" % msg) #short messy in user mode
         sys.exit(1)         #set errorlevel for script usage
diff --git a/tools/zolertia/z1-bsl b/tools/zolertia/z1-bsl
index 3fe6dfac14c1654bad79731bab04c409339075f5..d9db8bb21f21169042d607209d61f6bfc773f52b 100755
--- a/tools/zolertia/z1-bsl
+++ b/tools/zolertia/z1-bsl
@@ -1924,6 +1924,6 @@ if __name__ == '__main__':
         sys.exit(1)         #set errorlevel for script usage
     except Exception, msg:  #every Exception is caught and displayed
         if DEBUG: raise     #show full trace in debug mode
-        #sys.stderr.write("\nAn error occoured:\n%s\n" % msg) #short messy in user mode
+        #sys.stderr.write("\nAn error occurred:\n%s\n" % msg) #short messy in user mode
         #sys.exit(1)         #set errorlevel for script usage
         main(0);
diff --git a/tools/zolertia/z1-bsl-nopic b/tools/zolertia/z1-bsl-nopic
index 8b5edd8f5947497b210e26e7b086e12a231af027..f3685b0751918d49736ba30d19460265d8031615 100755
--- a/tools/zolertia/z1-bsl-nopic
+++ b/tools/zolertia/z1-bsl-nopic
@@ -1936,6 +1936,6 @@ if __name__ == '__main__':
         sys.exit(1)         #set errorlevel for script usage
     except Exception, msg:  #every Exception is caught and displayed
         if DEBUG: raise     #show full trace in debug mode
-        #sys.stderr.write("\nAn error occoured:\n%s\n" % msg) #short messy in user mode
+        #sys.stderr.write("\nAn error occurred:\n%s\n" % msg) #short messy in user mode
         #sys.exit(1)         #set errorlevel for script usage
         main(0);