Downgrading firmware on 5312 phones 1

[colpot]

Can anyone advise if its possible to downgrade the firmware on new 5312 phones to work with 4.0 SP2?
Am seeing differing opinions but wondered if anyone has actually managed to downgrade.
Thanks

Colpot
(Remember - If it aint broke - fix it till it is.)

 

[sarond]

Yes should be no problem, there was an issue with new phones being shipped out with newer FW and wouldn't downgrade to a pre MCD 5 system.

53xx series phones are preloaded 6.2.0.x firmware version. The 6.2.0.x firmware version is not allowed to download to pre-4.1.1.x firmware version. When these sets are registered to pre-MCD 5.0, they would fail to downgrade with an error of L2 DL Error. They could then reset and repeat with same cycle

You need to have a specific version loaded on your controller or TFTP Server, 4.1.1.7

There is an article on KMS. Search for the below.

5312/24/30/40 IP phone fails to boot with L2 DL error
MN00574838

Legacy Document ID
15-5191-00358