H1B transfer - over 1 year and no result. What to do?

Hi all.

Long story short: Initiated H1b transder July 2017. Got one RFE, responded.

Upgraded to PP.
Then in winter 2018 got another RFE, responded ASAP, and it says response received on USCIS/DHS website.

No Updates since then. It’s been approx 1 year since I heard back from USCIS and it’s with premium processing.
Raised SRE one, got “security check pending” status with no extra deatils.

Does anyone have thoughts what I can do?

Security checks cannot be overridden by premium processing timeline.

Unfortunately, there is nothing that you can do except to wait.

The most common reason for security check is change of address.
Have you been changing your US address frequently in past?

No changes in address in past few years.

Then, i am not sure why your case has been sent to security check.