Upgrading pair C6807-XL, SUP 6T to 15.5.1-SY6

[Jo49201]

Hello we will be upgrading a pair of C6807-XL,  for a client.
We will go for the ''Fast Software Upgrades'' since it's the safest upgrade and the VSS is not is full production so we can have small down time.
Upgrading from 15.5.1-SY5 to 15.5.1-SY6.

We change the boot system flash , reboot them, one at a time.  The FPGA should be upgrade automatically.
Do you know how much time those take?

Any other issue we should be looking forward too? I did check the release note. 

Will open a case for the upgrade when the date will be fix. 

Thank you. 

[Leo Laohoo]

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@Jo49201 wrote:

We will go for the ''Fast Software Upgrades'' since it's the safest upgrade and the VSS is not is full production so we can have small down time.

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I hate to be the guy to burst your bubble but I am afraid I have some seriously bad news.  

It is very important to read the 15.5(1)SY Release Notes very, very carefully.  The Release Notes have some "funny" information about manually performing FPGA upgrade on some line cards.  It is "funny" because the FPGA command is "hidden".  This manual FPGA is not supported in FSU/eFSU nor ISSU.  

Please read THIS.

[Jo49201]

Thank you for the reply,
I'm not sure if that is going to apply since we are already on 15.5.1-SY5.
But I will make sure to have console access for sure, and will look closely at that.