As of this morning - 1.12 of the firmware gives you 29.80.0.60 for the T42's - from the Yealink release notes for 29.80.0.70 quote:
"Fixed the issue that the user couldn’t hear any audio with T4 series phones when
the firmware was upgraded to the newly version of 80."
Fixed the issue? Issue? The firmware in 1.12 basically kills the phone - no audio = no phone!
It's easy enough to download 29.80.0.70 from their website and put it into the yealink/1 directory as t42.rom and have the phones use it, but this would be terrible for a new deployment that didn't know any better!
Same problems a few weeks ago with the BLF's on the T4 series - I am guessing that Yealink has changed the default, but it used to be that an Idle BLF showed green when the monitored phone was idle, and red when it was in use - the new default seems to be dark for idle and red for in use. This probably makes the LED last longer, but customers perceive it as a malfunction when the were used to the old behavior.
I would put this in the Yealink forum, but there is no Yealink forum. What happened with Yealink? Did they fire the only smart person they had? Things like this have been cropping up for months with all the various firmware's for the phones - we were even having a problem with T21P's at a client site that they couldn't talk to Cel Phones on certain carriers - firmware shouldn't cause that kind of problems!
Is it time to start looking around for phones again? People love the T48G's and we primarily sell them, but this is expensive to chase a working firmware, and it makes our systems look BAD!