IOS Upgrade problem

[nwizard]

Hi ! I have a problem with customer's 3640 router - after loading new version of Enterprise IOS the router lost all of interfaces. The same situation if I load IP Plus/FW/IDS feature set. IOS version is 12.1(7)

[barnetth]

It could be that the Network Modules installed in the 3640 are not supported on that perticular IOS version. Have you used the Hardware & Software Matrix tool ? Also check the amount of memory on the box.

[nwizard]

Interfaces are very similar - 3 FastEthernet modules. IOS 12.1(9), 12.2(1) official releases.

Yes, I used H&S Matrix Tool, but I still can't understand why it doesn't work... It was fixed when I used IOS with T suffix (like 12.1(7)T)

Amount of memory comform to IOS requirements - 64 mb