EC20, firmware update needed?

IoT Modules LTE Standard Module
1

Hi,

I’m running an EC20CEFDG module with firmware EC20CEFDGR08A02M4G on LG U+ (45006). The modem attaches to LTE normally, SMS works, data works, IMS is enabled, and the ims APN is set up.

The issue is that voice calls behave differently depending on the destination:

Calls to LG U+ mobile numbers alert but then drop with NO CARRIER.
Calls to KT mobiles connect fine.
Calls to LG U+ IP phones connect fine.
Service code 114 also works.

I tried the usual settings (dedicated IMS APN, UA string set to TTA-VoLTE/2.0 … LGU, AMR codecs enabled, just in case), but it doesn’t change the behavior.

I know that with firmware EC20CEFDGR06A11M4G this use case already works on LG U+, but with R08A02M4G I’m seeing this problem.

Is there any known difference in VoLTE handling between these firmware versions, or a patch that needs to be applied for R08A02M4G?

Thanks.

2

Hi,
Thank you for your detailed description.
Based on the two provided versions, these are two different baseline versions, one R06 and one R08. There must be differences between these two versions.
I haven’t seen the archived firmware for the R08 version. Could you please tell me how you obtained the version? I will check with the internal team and give you feedback later.

3

Hi Anna,

Thanks for the reply. The module came with EC20CEFDGR08A02M4G pre-installed (purchased from AliExpress).

Can you clarify what the differences are between the R06 and R08 baselines? If R06A11M4G is the supported release for LG U+ VoLTE, is it possible for me to re-flash this module back to the R06 firmware package?

4

Hi
Thank you for your reply.
I’ve confirmed internally that we no longer have R08 firmware. You can try upgrading to R06 and test whether it works properly.