BGP with password not working after forced transition from OpenBGP to FRR at upgrade

[Clint 0]

Upgraded to 2.5.1 from 2.4.4. Got surprised by removal of OpenBGP. No matter, needed to move to FRR anyway.

Re-keyed configs for BGP peers using backup from OpenBGP as a cheatsheet, one ISP came up without a hitch.

Second ISP uses a password, and will not come up. Tried all permutations of the "password type" dropdown without joy.

The salient line from the "old" (OpenBGP config:)

tcp md5sig password <passwordstring>

FRR shows the neighbor as "active" but not passing any messages. Never enters "established" state. Packet captures show traffic passing back and forth occasionally, I suspect that it's just each end trying to "wake" the other end.

The Question:

What's different about the password options available between OpenBGP and FRR? Specifically, can FRR be cajoled into working the same way OpenBGPd did with the config line above?

Thanks for any help,

Clint