Writing arbitrary data via the AT interface is blocked in production builds of v104. However, research indicates that glitching the power supply during the execution of an AT command can bypass the signature check, allowing an attacker to "write" modified firmware to the device.
Ensure the TX (Transmit) pin of the adapter connects to the RX (Receive) pin of the module, and vice versa. Cross-connecting is mandatory. write at command station v104 download top