In field update questions

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1

Hi All,

I’ve had a look around but can’t find any answers to these couple of questions:

In the documentation for SystemUpdate at ([url]http://www.ghielectronics.com/downloads/NETMF_Beta/Library%20Documentation/html/53c9fe92-8150-bd36-e2de-bf4fc6f13f8f.htm[/url] it says Extended Weak References kept are kept for a full update, are they kept OK when doing an ApplicationUpdate, or are they deleted? (assume they are kept since its a ‘smaller’ update)

Also, it says that [italic]"Note that you only need your application hex file and NOT the key or the signature file "[/italic]. Does this mean that any HEX file can be loaded though in field update, or does it check the signature of the hex compared to the previous application. Basically if I want to make sure it can only be updated with HEX files I specify, do i need to build that into the logic before loading the HEX file? (e.g. compare SHA1 of HEX file to a known valid signature?)

It’s great to have such functionality available, I’m trying to get prototype out to be tested at a couple of sites, and knowing that I can trigger updates remotely is going to save a lot of time (travel time at a minimum!) and hassles when that inevitable bug raises its nasty head. Well done!!!

Cheers

Ross

2

[quote]In the documentation for SystemUpdate at (http://www.ghielectronics.com/downloads/NETMF_Beta/Library%20Documentation/html/53c9fe92-8150-bd36-e2de-bf4fc6f13f8f.htm it says Extended Weak References kept are kept for a full update, are they kept OK when doing an ApplicationUpdate, or are they deleted? (assume they are kept since its a ‘smaller’ update)
[/quote]
Correct. This is application only update. Anything else (including EWR) are not touched.

[quote]Also, it says that "Note that you only need your application hex file and NOT the key or the signature file ". Does this mean that any HEX file can be loaded though in field update, or does it check the signature of the hex compared to the previous application. Basically if I want to make sure it can only be updated with HEX files I specify, do i need to build that into the logic before loading the HEX file? (e.g. compare SHA1 of HEX file to a known valid signature?)
[/quote]
You just need to pass on the generated HEX file. See the example. We do not do any verification…

3

I like to add that you can add encryption/signature-checking or any means of protecting your device/firmware. We leave this out so you can implement it anyway you like.