All MaxxECUs supports the GEN1 8HP control for the 8HP45, 8HP70 and 8HP90 gearboxes, and you can use it as a standalone TCU controller, but you need to be aware of certain things, see 8HP CAN protocol.

Will update the MaxxECU system with 8HP gear and vehicle speed. Speed/gear --> Speed/Gear.

Speed/gear --> Sensor setup, driven wheel sensor setup. When enabled as driveshaft, the 8HP control will update MaxxECU driveshaft.
This is likely caused by incorrect TCU wiring, where the main power supply and the wake-up power have been connected in parallel.
The power-up sequence is critical. The main power supply must be active continuously (or at least 10–15 s) before the wake-up signal is applied. If not, part of the TCU will fail to initialize and the paddles will not function in manual mode.