Fallback OS Catalyst 3850 Series

[Mohamad Lukman]

Hi everyone,

we will plan to upgrade the Catalyst 3850 Series OS, the OS version 16.6.4a is now installed and we want to upgrade to 16.12.11,
I have found how to install/upgrade in the attached link.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/16-3/release_notes/ol-16-3-3850.html

However, we had difficulty finding documents on how to fall back to the original OS, and we tried to find the old OS on our device
file (.bin) not found.

Please help, how do I fallback the OS to everything?

thanks

[johnlloyd_13]

hi,

you can "downgrade" using the #request platform software package install privilege exec command. see link below:

https://wannabelab.blogspot.com/2023/04/cisco-3850-switch-ios-xe-downgrade-16x.html

just file transfer the target lower version IOS-XE via USB or FTP/TFTP.

[Mohamad Lukman]

The method is exactly the same as installing the upgrade, right?

Upgrades
copy tftp://192.168.1.10/os-upgrade.bin flash:os-upgrade.bin
Install
request platform software package install switch all files flash:os-upgrade.bin new auto-copy

Downgrade
copy tftp://192.168.1.10/os-downgrade.bin flash:os-downgrade.bin
Install
request platform software package install switch all files flash:os-downgrade.bin new auto-copy

Like this?

[Leo Laohoo]

Post the complete output to the command "dir". 

If the Install Mode was done correctly, there should be two "packages.conf" files: 

1.  First packages.conf file will point to the new firmware. 
2.  Second packages.conf file, maybe called packages.conf.00-, will point to the old firmware. 

Fall-back is easy: 

1.  Rename "packages.conf" to something else, like "package.conf.bak". 
2.  Rename "packages.conf.00-" to "packages.conf".  
3.  Check the contents of "packages.conf" to see what firmware it will boot:  more flash:packages.conf | begin for NOVA
4.  If all looks correct, reboot.

[Mohamad Lukman]

okay, thank you for the information provided,

how to rename "packages.conf" to "packages.conf.bak"?

just rename packages.conf, then reload, right?

[Leo Laohoo]

---

@Mohamad Lukman wrote:
how to rename "packages.conf" to "packages.conf.bak"

---

rename flash:packages.conf flash:packages.conf.bak

[Mohamad Lukman]

==Downgrade==

LAB# dir flash:
packages.conf (new version)
packages.conf.xx (old version)

LAB# rename flash:packages.conf(new version) flash:packages.conf.bak
LAB# rename flash:packages.conf.xx (old version) flash:packages.conf

LAB#show boot
---------------------------
Switch 1
---------------------------
Current Boot Variables:
BOOT variable does not exist

Boot Variables on next reload:
BOOT variable = flash:packages.conf
Manual Boot = no
Enable Break = no
Boot Mode = DEVICE
iPXE Timeout = 0
LAB#
LAB#reload

Like this, right?

[Leo Laohoo]

Post the complete output to the command "more flash:packages.conf | begin for NOVA".

[Mohamad Lukman]

Hi Leo,
we have another new case, the current status of the 3850 switch is 2 switch mode-stack, and the upgrade plan will be to remove stack-mode, and will
upgrade per switch, which is our question;

1. Is there any configuration for routing, VLAN, etc. on the 2 switches after removing stack-mode?
2. Can you share with us how to remove stack-mode on Switch3850?

[Leo Laohoo]

---

@Mohamad Lukman wrote:
Can you share with us how to remove stack-mode on Switch3850?

---

conf t
 no switch 2 provision <MODEL>
end

[Leo Laohoo]

---

@Mohamad Lukman wrote:
Is there any configuration for routing, VLAN, etc. on the 2 switches after removing stack-mode?

---

1. Power down switch 2. 
2. Remove stacking cable from switch 1 and switch 2. 
3. Remove switch 2 from the rack
4. Renumber switch 2 to switch 1 (for future deployment) & wipe the config or perform factory reset.