KC868-A2 SIM7600 with Tuya GPRS not work

[admin]

if you have tuya license, your A2 board + SIM7600 can work with tuya app. download KCS v2 firmware, enable 4G and tuya app.

[WestfieldGhost]

Hello,
my KC868-A2 is LTE-only, it is never connected to LAN or Wi-Fi.
1. The firmware provides no LTE data support
There is no LTE option in the UI — only “GPRS”, and there are no APN or PDP settings.
Because of this, the SIM7600 cannot use mobile data for Tuya or MQTT.
2. Tuya does not work over mobile data
When GPRS is enabled, Tuya always stays disconnected, even with Ethernet unplugged.
3. MQTT also does not work over mobile data
MQTT connects only when the board is on LAN/Wi-Fi.
With LTE/GPRS only, MQTT never connects.
4. LTE modem itself works correctly
When the SIM7600 is connected directly to a PC, LTE works perfectly (APN OK, NETOPEN OK, mobile IP assigned).
So the modem and SIM card are fine.
Question

Does the KC868-A2 support Tuya or MQTT over LTE data at all? If yes, which firmware version enables this?

Board Model KC868_A2 Software
Version v2.2.17 
Build Date Nov 16 2025 14:14:44 
Serial Number 8813BFB4F384

[alexps70]

if you have tuya license, your A2 board + SIM7600 can work with tuya app. download KCS v2 firmware, enable 4G and tuya app.

У меня есть лицензия, но Tuya работает только через LAN/Wifi

[admin]

we will check it.

[admin]

you can test with this new firmware for KC868-A2

  KCS_KC868_A2_V2.2.18_beta_20251201-223646.zip (Size: 762.65 KB / Downloads: 9)

[WestfieldGhost]

Hello everyone,

thank you very much for providing the new beta firmware V2.2.18.
I have tested it together with my KC868-A2 and a SIM7600E-L1C module.

Unfortunately, even with this new firmware, both MQTT and Tuya still do not connect over LTE/GPRS, although they work correctly when the board is on LAN or Wi-Fi.

To confirm that the issue is not related to the SIM7600 hardware or the mobile network, I performed several additional tests:
• The SIM7600E-L1C registers in LTE (Band 1) without problems.
• APN and PDP context are working correctly when the module is tested directly via AT commands on a PC.
• Internet access through LTE works reliably (HTTP 200 responses).
• Baud rate, LTE mode (CNMP=38), and factory settings were all verified.

So LTE connectivity itself is fine, but the KC868 firmware still does not seem to use LTE data for Tuya or MQTT.

Before I continue testing:
Has anyone else already tried this new firmware V2.2.18 with LTE-only operation?
Did you have any success with Tuya or MQTT over LTE, or do you have any additional findings?

Any feedback from other users would be very helpful.

Thank you.