Load Custom Firmware Doesn't work

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Compile from ArduPilot Arduino 1.0.3
2. Run mission planner 1.2.69 mav 1.0, Connect then Initial Setup, Install 
Firmware
3. Run Load custom firmware, then pick on .hex, say MyArduCopter.hex, displays 
on message window download~sending messages, then hangs.

What is the expected output? What do you see instead?
The previous version, 1.2.67 works smoothly, uploads and verifies the firmware 
installs till done without any issue. 

What version of the product are you using? On what operating system?
Mission Planner 1.2.69 running on windows 7 64 bit

Please provide any additional information below.
I always download latest AndroPilot commit from the trunk, add my own 
enhancements, then compile using Arduino 1.0.3, then load the .hex from Mission 
Planner's  Load custom firmware, which had always worked prior 1.2.69.

It the compile (.hex) uploads successfully using Arduino and also through 
Mission Planner if I revert back to version 1.2.67 i.e., prior 1.2.69.

Original issue reported on code.google.com by [email protected] on 14 Aug 2013 at 4:30