How to downgrade the firmware on JioFiber ONT. JCOW414 to be specific

[sameer7in7]

Hello, so i was trying to downgrade the firmware of jiofiber ONT inorder to achieve root access, since jio has patched almost all ways of getting potential root, i was thinking if flashing an older firmware might work. so i tried to get the old firmware for my ONT model from https://github.com/gpsarathy/JioFiber-Home-Gateway/tree/master/Firmwares/JCOW414/2.15 , however when i uploaded and clicked the upgrade button a warning came up that the firmware is invalid or corrupted.
Is Jio purposely not allowing downgrading of firmware? is there a way to bypass this? how does the router check if the firmware i am trying to install is older? is it by filename? will renaming help?

[itsyourap]

• The router doesn't check if the version name is older or not
• In the versions after 2.49, the public key for verification of the firmware signature has changed, thus you get the invalid firmware error
• Yes, it's possible to bypass if you have root access to the router