UT003 wireless module: Ebyte E101-C3MN4-XS (ESP32-C3)

Decided 2026-09-08 (written up 2026-10-19 from universal-tester-003, which holds the original log line). The UT003 board was scrapped 2026-10-14; the choice still applies to any tester that adds WiFi/BLE and OTA-flashes an STM32.

The decision

Ebyte E101-C3MN4-XS (ESP32-C3, 4 MB flash, IPEX antenna connector, 12.5 x 13.2 mm), not the Ebyte E103-W14X.

Why

The E103-W14X ships closed, AT-command-only firmware. Its manual does not state UART parity, binary transparency or remote GPIO control, and those three decide whether over-the-air flashing of the STM32 works. With the ESP32-C3 those become our problem to solve instead of an undocumented vendor behaviour, which is the safer side of the trade.

Do not re-argue

An AT-command module is rejected unless the vendor documents UART parity, binary-transparent mode and remote GPIO.