You need to update the firmware 1st.
This was a huge stink when Peerless released these 'CI friendly' outdoor TVs; and then find out they didn't have discrete codes.
I for one told the rep what an idiot the people at Peerless were for bringing such BS to the market. And that there is no way in hell any respectable CI would sell/install these turds.
It took a few years of horrible sales (and every dealer telling them why), before it got thru the thick skulls at Peerless and they came out with the firmware for discrete codes.

So, yes. Update the firmware and try the URC codes again.

Hopefully there was not a hardware change that took place as well. And even with new firmware, you can't get discrete control. That would suck.