Yeastar TG Gateway 4G VoLTE fix v91.3.37.3 (TGv3)

Author: Byron Paul

Date: 18/09/2026

With the shutdown of the 3G network in New Zealand some clients may have issues with 4G VoLTE calls. Symptoms are that enabling VoLTE the modems connects, but reports 2G connection & all calls fail or no network connection at all.

Yeastar is publishing a new firmware that addresses this in their general release firmware in the future, but in the meantime they currently provide a specific fix for this issue while awaiting the general release at https://www.yeastar.com/firmware-download/. 

V91.3.0.37.3 is available below. Apply in the upgrade section of the gateway System>>System Preferences>>Update System Firmware via HTTP, or download it to your own internal HTTP/TFTP server and apply from there.

Download link: http://downloads.snappernet.co.nz.s3.amazonaws.com/yeastar/TGv3_VoLTE/91.3.0.37.3.bin

NOTES:

• It is assumed the model is TGv3 - not applicable to TGv1
  • The modems should be 4G/LTE capable (modem models EC20, EC21 or EC25). To check see this KB
• "VoLTE" should be enabled in the GSM trunks (Mobile List->Edit->Advanced Settings->Enable VoLTE)
• In some situations you will also need to hard set the network type from 'Auto' to '4G only'
• How to upgrade: https://support.yeastar.com/hc/en-us/articles/8629958998553-How-to-upgrade-the-TG-TA-TE-gateway