[c-nsp] Upgrading 12K IOS XR from 3.6 to 4.2

[ibogzipper iboge]

Hi,
I'm in the process of upgrading 12K IOS XR from 3.6 to 4.2. But according
to cisco upgrade path its seems to be from 3.6 -> 3.9 , 3.9 - > 4.2 (
http://www.cisco.com/web/Cisco_IOS_XR_Software/index.html#XR12000) .
therefore i'm wondering that whether i can do turboboot . but there is no
reference regarding the minimum rommon required to load the 4.2 IOS XR in
turboboot ( min required is 1.24) . Also to upgrade the rommon there is no
package available on the download section ( archive also doesn't have
package)  .

Anyone having previous experience on 3.6 - > 4.2 upgrade ?


Thanks & regards