Good news. Thank you. I'm testing ver 86 now a T58 and so far so good. Have you had audio issues on longer calls? One version of the ver 85 firmware created 4min gaps in audio at random. I've been running on ver 84 as a result.I had lots of problems with Yealink T54W. From BLF not working to the transfer issue you are referring to. I am now using 22.214.171.124 and it has solved those problems.
On the T54W, the firmware does not appear on Yealink's site as of yet. Do you happen to have a copy of this firmware?