How to use 4x10g phy as bare 40g phy without MAC ip

Hi Enamorint, NativePHY IP is just like an open PHY IP where user can freely configure the IP to suit whatever need they want. Therefore, there is not specific doc for 40G PHY only but we have full complete MAC + PHY 40G solution IP user guide in below link https://www.intel.com/content/www/us/en/programmable/products/intellectual-property/ip/interface-protocols/m-alt-40gb-ethernet.html For your issue debug : 1) What test that you are trying to run here ? Is it some sort of loopback testing ? 2) and your doubt is why is it failing on hardware test but passed on simulation ? - You want to start check on the status signal as you indicated like lockedtoref and lockedtodat to see whether CDR indeed loose lock or not. Actual hardware behaviour is different from idle condition in sim world. Thanks. Regards, dlim