diff --git a/firmware/src_simtrace/main.c b/firmware/src_simtrace/main.c
index a7fa616..358ec65 100644
--- a/firmware/src_simtrace/main.c
+++ b/firmware/src_simtrace/main.c
@@ -77,6 +77,13 @@
 static volatile enum confNum simtrace_config = CFG_NUM_CCID;
 #endif
 
+static const Pin pin_hubpwr_override = PIN_PRTPWR_OVERRIDE;
+static const Pin pin_hub_rst = {PIO_PA13, PIOA, ID_PIOA, PIO_OUTPUT_1, PIO_DEFAULT};
+static const Pin pin_1234_detect = {PIO_PA14, PIOA, ID_PIOA, PIO_INPUT, PIO_PULLUP};
+static const Pin pin_peer_rst = {PIO_PA0, PIOA, ID_PIOA, PIO_OUTPUT_0, PIO_DEFAULT};
+static const Pin pin_peer_erase = {PIO_PA11, PIOA, ID_PIOA, PIO_OUTPUT_0, PIO_DEFAULT};
+
+
 /*----------------------------------------------------------------------------
  *       Callbacks
  *----------------------------------------------------------------------------*/
@@ -97,8 +104,15 @@
 	config_func_ptrs[simtrace_config].usart0_irq();
 }
 
-#include "i2c.h"
+static int qmod_sam3_is_12(void)
+{
+	if (PIO_Get(&pin_1234_detect) == 0)
+		return 1;
+	else
+		return 0;
+}
 
+#include "i2c.h"
 static int write_hub_eeprom(void)
 {
 	const unsigned char __eeprom_bin[] = {
@@ -127,17 +141,8 @@
 	};
 	const unsigned int __eeprom_bin_len = 256;
 
-	const Pin pin_hubpwr_override = PIN_PRTPWR_OVERRIDE;
-	const Pin pin_hub_rst = {PIO_PA13, PIOA, ID_PIOA, PIO_OUTPUT_1, PIO_DEFAULT};
 	int i;
 
-	/* set PIN_PRTPWR_OVERRIDE to output-low to avoid the internal
-	 * pull-up on the input to keep SIMTRACE12 alive */
-	PIO_Configure(&pin_hubpwr_override, 1);
-
-	PIO_Configure(&pin_hub_rst, 1);
-	i2c_pin_init();
-
 	/* wait */
 	volatile int v;
 	/* 440ns per cycle here */
@@ -145,6 +150,7 @@
 		v = 0;
 	}
 
+	TRACE_INFO("Writing EEPROM...\r\n");
 	/* write the EEPROM once */
 	for (i = 0; i < 256; i++) {
 		int rc = eeprom_write_byte(0x50, i, __eeprom_bin[i]);
@@ -154,6 +160,7 @@
 	}
 
 	/* then pursue re-reading it again and again */
+	TRACE_INFO("Verifying EEPROM...\r\n");
 	for (i = 0; i < 256; i++) {
 		int byte = eeprom_read_byte(0x50, i);
 		TRACE_INFO("0x%02x: %02x\r\n", i, byte);
@@ -169,6 +176,79 @@
 	return 0;
 }
 
+static void check_exec_dbg_cmd(void)
+{
+	uint32_t addr, val;
+
+	if (!UART_IsRxReady())
+		return;
+
+	int ch = UART_GetChar();
+	switch (ch) {
+	case '?':
+		printf("\t?\thelp\r\n");
+		printf("\tE\tprogram EEPROM\r\n");
+		printf("\tR\treset SAM3\r\n");
+		printf("\tO\tEnable PRTPWR_OVERRIDE\r\n");
+		printf("\to\tDisable PRTPWR_OVERRIDE\r\n");
+		printf("\tH\tRelease HUB RESET (high)\r\n");
+		printf("\th\tAssert HUB RESET (low)\r\n");
+		printf("\tw\tWrite single byte in EEPROM\r\n");
+		printf("\tr\tRead single byte from EEPROM\r\n");
+		printf("\tX\tRelease peer SAM3 from reset\r\n");
+		printf("\tx\tAssert peer SAM3 reset\r\n");
+		printf("\tY\tRelease peer SAM3 ERASE signal\n");
+		printf("\ty\tAssert peer SAM3 ERASE signal\r\n");
+		break;
+	case 'E':
+		write_hub_eeprom();
+		break;
+	case 'R':
+		NVIC_SystemReset();
+		break;
+	case 'O':
+		PIO_Set(&pin_hubpwr_override);
+		break;
+	case 'o':
+		PIO_Clear(&pin_hubpwr_override);
+		break;
+	case 'H':
+		PIO_Clear(&pin_hub_rst);
+		break;
+	case 'h':
+		/* high level drives transistor -> HUB_RESET low */
+		PIO_Set(&pin_hub_rst);
+		break;
+	case 'w':
+		if (PIO_GetOutputDataStatus(&pin_hub_rst) == 0)
+			printf("WARNING: attempting EEPROM access while HUB not in reset\r\n");
+		printf("Please enter EEPROM offset: ");
+		UART_GetIntegerMinMax(&addr, 0, 255);
+		printf("Please enter EEPROM value: ");
+		UART_GetIntegerMinMax(&val, 0, 255);
+		printf("Writing value 0x%02x to EEPROM offset 0x%02x\r\n", val, addr);
+		eeprom_write_byte(0x50, addr, val);
+		break;
+	case 'r':
+		printf("Please enter EEPROM offset: ");
+		UART_GetIntegerMinMax(&addr, 0, 255);
+		printf("EEPROM[0x%02x] = 0x%02x\r\n", addr, eeprom_read_byte(0x50, addr));
+		break;
+	case 'X':
+		PIO_Clear(&pin_peer_rst);
+		break;
+	case 'x':
+		PIO_Set(&pin_peer_rst);
+		break;
+	case 'Y':
+		PIO_Clear(&pin_peer_erase);
+		break;
+	case 'y':
+		PIO_Set(&pin_peer_erase);
+		break;
+
+	}
+}
 
 /*------------------------------------------------------------------------------
  *        Main
@@ -204,10 +284,28 @@
 		   g_unique_id[0], g_unique_id[1],
 		   g_unique_id[2], g_unique_id[3]);
 
-	write_hub_eeprom();
+	/* set PIN_PRTPWR_OVERRIDE to output-low to avoid the internal
+	 * pull-up on the input to keep SIMTRACE12 alive */
+	PIO_Configure(&pin_hubpwr_override, 1);
+	PIO_Configure(&pin_hub_rst, 1);
+	PIO_Configure(&pin_1234_detect, 1);
+	PIO_Configure(&pin_peer_rst, 1);
+	PIO_Configure(&pin_peer_erase, 1);
+	i2c_pin_init();
+
+	if (qmod_sam3_is_12()) {
+		TRACE_INFO("Detected Quad-Modem ST12\r\n");
+	} else {
+		TRACE_INFO("Detected Quad-Modem ST34\r\n");
+	}
+
+	while (1) {
+		check_exec_dbg_cmd();
+	}
 
 	TRACE_INFO("USB init...\r\n");
 	while (USBD_GetState() < USBD_STATE_CONFIGURED) {
+		check_exec_dbg_cmd();
 #if 0
 		if (i >= MAX_USB_ITER * 3) {
 			TRACE_ERROR("Resetting board (USB could "
@@ -218,6 +316,9 @@
 		i++;
 	}
 
+	TRACE_INFO("Releasing ST12_PRTPWR_OVERRIDE\r\n");
+	PIO_Clear(&pin_hubpwr_override);
+
 	TRACE_INFO("calling configure of all configurations...\r\n");
 	for (i = 1; i < sizeof(config_func_ptrs) / sizeof(config_func_ptrs[0]);
 	     ++i) {
@@ -236,6 +337,7 @@
 		putchar('\b');
 		putchar(rotor[i++ % ARRAY_SIZE(rotor)]);
 #endif
+		check_exec_dbg_cmd();
 
 		if (USBD_GetState() < USBD_STATE_CONFIGURED) {