the target starts up and works for a few seconds before crashing. Good enough for others to continue the work :-)

variants/ai-c3/platformio.ini

@@ -0,0 +1,8 @@
+[env:ai-c3]
+extends = esp32c3_base
+board = esp32-c3-devkitm-1
+board_level = extra
+build_flags = 
+  ${esp32_base.build_flags}
+  -D PRIVATE_HW
+  -I variants/ai-c3

variants/ai-c3/variant.h

@@ -0,0 +1,26 @@
+// #define BUTTON_NEED_PULLUP // if set we need to turn on the internal CPU pullup during sleep
+
+#define I2C_SDA 8
+#define I2C_SCL 9
+
+#define BUTTON_PIN 0
+
+#define USE_RF95
+#undef RF95_SCK
+#define RF95_SCK 4
+#undef RF95_MISO
+#define RF95_MISO 5
+#undef RF95_MOSI
+#define RF95_MOSI 6
+#undef RF95_NSS
+#define RF95_NSS 7
+
+#define LORA_DIO0 10 // a No connect on the SX1262 module
+#define LORA_DIO1 3  // a No connect on the SX1262 module
+#define LORA_RESET 2
+
+#undef GPS_RX_PIN
+#undef GPS_TX_PIN
+
+#define HAS_SCREEN 0
+#define HAS_GPS 0