ECS4510

Hello,
I have three ECS4510-28F switches, but unfortunately we no longer know the logins to them. And there is no hardware button to hard reset them.

I have tried:

1. guest account - but it is disabled

2. ctrl+u during boot and the password mercury - nope

3. loop between port 1 and 2 - nothing

Do you have any other idea how to reset it?

Thank you,
Vasek