How to disable USART bootloader?

[morpeh89]

Posted on May 25, 2010 at 09:12

How to disable USART bootloader?

[damh]

Posted on May 17, 2011 at 13:52

If you use a BGA, you can tie the pins (BOOT0, BOOT1) to internal layers. Normal users won't have access to internal bootloader anymore.

But I think the internal bootloader is more secure than an open JTAG interface ;) The second question is discussed in other threads. The normal way from JTAG or internal bootloader: You have to disable read protection first (before you are able to disbable the write protection). Disabling read protection starts a mass erase. After the erase has been completed, the option bytes will be erased. Then you need a reset to use the new option bytes. But I think that there is a second way (backdoor).

[Tesla DeLorean]

Posted on May 17, 2011 at 13:52

Have to agree with damh here, the USART bootloader is fairly secure, and certainly more so than JTAG, where you'd be able to sniff RAM content. It is also much easier to use in a production environment.

Most of your security issues will be with field updates. Anyone with any real talent/equipment will be able steal your code, even if they have to destroy the device to get at it.