Solved Yealink T27G Firmware Won't Update after v16 upgrade

[fsdfdsfs]

So a client of ours has 30 Yealink T27G phones and were on v15.5 of 3CX with supported Yealink Firmware 69.83.0.55.

After the update to v16 of 3CX we tried to update the firmware to v69.84.0.95 but could not do it. I then factory reset the T27G phone and tried to update the firmware on the phones and could not do it. I then tried to install a older firmware on the phone and could not do it. I could not update to a newer firmware or an older firmware. I then opened a ticket with Yealink and they sent me this link to this file which allowed me to downgrade the phones and I was then able to update the firmware to 69.84.0.95.

Yealink supplied a link to a T27G-69.83.0.199.rom file

We were able to update the firmware using this link and 69.83.0.199.rom and could then put the supported firmware on the phone.

 

[AWS2P]

Frequent problem when fw release are too far, surely it was most probably your case and since you apply intermediate level given from Yealink, then FW becomes enough close to be updated to latest

 

[JohnS_3CX]

Hi Ron,

Thanks for sharing your solution, I removed the link for security purposes, but people can reach Yealink to help them if needed.

This is not a rare matter, and it's one of the reasons why we recommend to people to keep their PBX and firmware updated when we make new releases, so they don't fall to far behind and lose compatibility.

The reasoning behind it is that phone manufacturers usually want to keep tight control over the way firmware is updated to ensure that it goes smoothly and does not brick the phone. So according to their tests they may block a new version of firmware from installing on the device until you get the in between updates that came out chronologically. Sometimes its a single ROM, sometimes it may be 2-3 depending on the case. Regardless of the brand, they usually keep the in between versions on their websites to facilitate this.