diff --git a/.github/workflows/pr-build-check.yml b/.github/workflows/pr-build-check.yml
index cebf0cfe..acf824bd 100644
--- a/.github/workflows/pr-build-check.yml
+++ b/.github/workflows/pr-build-check.yml
@@ -40,6 +40,8 @@ jobs:
           - PicoW_repeater
           # STM32
           - wio-e5-mini_repeater
+          - ebyte_e22p_f103_kiss_modem_uart
+          - ebyte_e22p_f103_kiss_modem_usb
           # ESP32-C6
           - LilyGo_Tlora_C6_repeater_
           # LR1110 (nRF52)
diff --git a/variants/ebyte_e22p_f103/platformio.ini b/variants/ebyte_e22p_f103/platformio.ini
new file mode 100644
index 00000000..aed5b6ae
--- /dev/null
+++ b/variants/ebyte_e22p_f103/platformio.ini
@@ -0,0 +1,69 @@
+; EBYTE E22P-915MBH-SC evaluation kit: STM32F103C8T6 + E22P-915M30S (SX1262, 30 dBm PA).
+; Minimal KISS TNC, no crypto/identity/filesystem.
+; Pin map taken directly from the kit schematic (E22(220)-400(900)MBH-SC).
+[ebyte_e22p_f103]
+extends = stm32_base
+board = genericSTM32F103C8
+build_flags = ${stm32_base.build_flags}
+  -D RADIO_CLASS=CustomSX1262
+  -D WRAPPER_CLASS=CustomSX1262Wrapper
+  -D KISS_NO_CRYPTO=1
+  ; --- SX1262 wiring (SPI1: SCK PA5 / MISO PA6 / MOSI PA7) ---
+  -D P_LORA_NSS=PA4
+  -D P_LORA_DIO_1=PA3
+  -D P_LORA_BUSY=PB1
+  -D P_LORA_RESET=PB0
+  ; --- RF switch: E22 PA/LNA controlled by TXEN (DIO2 NOT used as switch) ---
+  ; PB13 is the E22P EN line: forced HIGH in EByteE22PF103Board::begin(), NOT driven by
+  ; RadioLib. SX126X_RXEN is intentionally left undefined so RadioLib doesn't fight it;
+  ; CustomSX1262::std_init() supplies RADIOLIB_NC for RXEN when only TXEN is set.
+  -D SX126X_TXEN=PB12
+  ; --- E22 module has a TCXO on DIO3 ---
+  -D SX126X_DIO3_TCXO_VOLTAGE=1.8
+  -D SX126X_CURRENT_LIMIT=140
+  -D SX126X_RX_BOOSTED_GAIN=1
+  ; --- TXD LED = PA15 (JTDI), active-low. EByteE22PF103Board::begin() does the SWJ
+  ; NOJTAG remap to free the pin (SWD flashing/debug unaffected). ---
+  -D P_LORA_TX_LED=PA15
+  ; --- 915 MHz module (US band); tune to taste ---
+  -D LORA_FREQ=915.0
+  ; WARNING: this is a 30 dBm (1W) PA module. LORA_TX_POWER sets the *SX1262*
+  ; drive level, which the external PA amplifies. Set per Ebyte's PA spec;
+  ; over-driving can exceed legal limits / overheat the module.
+  -D LORA_TX_POWER=22
+  -I variants/ebyte_e22p_f103
+build_src_filter = ${stm32_base.build_src_filter}
+  +<../variants/ebyte_e22p_f103>
+  ; STM32F1 has no SHUTDOWN-mode flash FS; KISS_NO_CRYPTO never uses it, and its flash
+  ; program path (FLASH_TYPEPROGRAM_DOUBLEWORD) isn't F1-safe anyway.
+  -<helpers/stm32/InternalFileSystem.cpp>
+; F103 has no SubGHz radio peripheral (that's an STM32WL-only block); stm32_base pulls
+; the SubGhz lib in for those boards, so drop it here or it fails to compile.
+lib_ignore = SubGhz
+
+; ---- KISS over the broken-out USART1 header (PA9 TX / PA10 RX) ----
+[env:ebyte_e22p_f103_kiss_modem_uart]
+extends = ebyte_e22p_f103
+build_src_filter = ${ebyte_e22p_f103.build_src_filter}
+  +<../examples/kiss_modem/>
+
+; ---- KISS over the Type-C native USB (CDC); fit is tighter ----
+[env:ebyte_e22p_f103_kiss_modem_usb]
+extends = ebyte_e22p_f103
+build_flags = ${ebyte_e22p_f103.build_flags}
+  -D USBCON
+  -D USBD_USE_CDC
+  -D USBD_VID=0x0483
+  -D USBD_PID=0x5740
+  ; The default 3-packet (192B) CDC receive ring fills mid-burst on a large host->modem
+  ; KISS frame (~5 back-to-back 64B USB packets), forcing pause/resume of reception from
+  ; the MAIN thread, which races the USB ISR in CDC_ReceiveQueue_ReserveBlock and can hand
+  ; the endpoint a torn block pointer -> USB_ReadPMA writes out of bounds -> HardFault
+  ; (hardware-observed: imprecise bus fault, pc in USB_ReadPMA, lr in USB IRQ handler).
+  ; 16 packets (1024B) holds the largest single-flight KISS exchange, so the queue never
+  ; fills and the racy resume-from-main-thread path never runs. (#ifndef-guarded.)
+  -D CDC_RECEIVE_QUEUE_BUFFER_PACKET_NUMBER=16
+  -flto
+build_unflags = -fno-lto
+build_src_filter = ${ebyte_e22p_f103.build_src_filter}
+  +<../examples/kiss_modem/>
diff --git a/variants/ebyte_e22p_f103/target.cpp b/variants/ebyte_e22p_f103/target.cpp
new file mode 100644
index 00000000..161c21ed
--- /dev/null
+++ b/variants/ebyte_e22p_f103/target.cpp
@@ -0,0 +1,22 @@
+#include <Arduino.h>
+#include "target.h"
+
+EByteE22PF103Board board;
+
+// External SX1262 on the default SPI bus. NSS / DIO1 / RESET / BUSY are wired
+// to GPIOs; SCLK/MISO/MOSI use the F103's default SPI1 pins (PA5/PA6/PA7).
+RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY);
+
+WRAPPER_CLASS radio_driver(radio, board);
+
+VolatileRTCClock rtc_clock;
+SensorManager sensors;
+
+bool radio_init() {
+  return radio.std_init();
+}
+
+mesh::LocalIdentity radio_new_identity() {
+  RadioNoiseListener rng(radio);
+  return mesh::LocalIdentity(&rng);  // create new random identity
+}
diff --git a/variants/ebyte_e22p_f103/target.h b/variants/ebyte_e22p_f103/target.h
new file mode 100644
index 00000000..5b3fb934
--- /dev/null
+++ b/variants/ebyte_e22p_f103/target.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/radiolib/RadioLibWrappers.h>
+#include <helpers/stm32/STM32Board.h>
+#include <helpers/radiolib/CustomSX1262Wrapper.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/SensorManager.h>
+
+// EBYTE E22P-915MBH-SC evaluation kit: STM32F103C8T6 ("Blue Pill"-class MCU,
+// Cortex-M3, 64KB flash, 20KB SRAM) + E22P-915M30S (SX1262, 30dBm PA).
+// External SX1262 LoRa radio on the default SPI1 bus (PA5/PA6/PA7).
+// No on-chip filesystem / identity is used (KISS_NO_CRYPTO build).
+class EByteE22PF103Board : public STM32Board {
+public:
+  void begin() override {
+    // Free PA15 (JTDI) for the TX LED: switch the debug port to SW-DP only (drops the
+    // 5-wire JTAG, keeps 2-wire SWD, so flashing/debug via ST-Link is unaffected). Must
+    // run before anything configures PA15.
+    __HAL_RCC_AFIO_CLK_ENABLE();
+    __HAL_AFIO_REMAP_SWJ_NOJTAG();
+
+    STM32Board::begin();
+
+    // E22P EN line forced high (RadioLib does not drive it as an RF switch pin).
+    pinMode(PB13, OUTPUT);
+    digitalWrite(PB13, HIGH);
+
+#if defined(P_LORA_TX_LED)
+    // TX-activity LED (active-low). STM32Board::onBeforeTransmit/onAfterTransmit toggle
+    // it; configure the pin here since the base class never does.
+    pinMode(P_LORA_TX_LED, OUTPUT);
+    digitalWrite(P_LORA_TX_LED, HIGH);  // off
+#endif
+  }
+
+  const char* getManufacturerName() const override {
+    return "EBYTE E22P F103 KISS";
+  }
+};
+
+extern EByteE22PF103Board board;
+extern WRAPPER_CLASS radio_driver;
+extern VolatileRTCClock rtc_clock;
+extern SensorManager sensors;
+
+bool radio_init();
+mesh::LocalIdentity radio_new_identity();