CISCO ASR 1002-X upgrade from 3.16.5S to 17.3.5

[whizkidraj]

Dear Cisco Community, and @Leo Laohoo,

I have to upgrade two Cisco ASR 1002-X Routers.

Current version is: asr1002x-universalk9.03.16.05.S.155-3.S5-ext.SPA.bin (3.16.5S)

Version to upgrade to: asr1002x-universalk9.17.03.05.SPA.bin (17.3.5)

Current Rommon version is not shared by the client,
but rommon version to upgrade to should be the latest right now, right, i.e.
asr1000-rommon.173-1r.SPA.pkg - Release 17.3(1r)

1. Please check if all above links are correct.

2. Can I upgrade direct from above current version to suggested upgrade version i.e. from 3.16.5S to 17.3.5.

Or is there any upgrade path for this.

3. If there's any upgrade path, please do share the upgrade path for my current version to suggested version i.e. from 3.16.5S to 17.3.5 (and also the rommon software package).
4. Please share the upgrade steps.

5. Since this is IOS XE, like 3850 switch, do we have 2 types of upgrade in ASR routers too i.e. Bundle and Install mode.

6. If yes then please share upgrade steps for both.

[Leo Laohoo · Accepted solution]

Refer to this:  Cisco ISR & ASR 1k Routers: IOS-XE/Firmware Upgrade (Install Mode)

Here are the steps: 

1. Upgrade the ROMMON but DO NOT REBOOT. 
2. Unpack the BIN file (Install Mode)
3. Change the boot variable string to point to

   packages.conf.

    
4. Verify (refer to my document)
5. Reboot.