diff --git a/firmware/common/operacake.c b/firmware/common/operacake.c
index 5cbf77c8..f62cd5cf 100644
--- a/firmware/common/operacake.c
+++ b/firmware/common/operacake.c
@@ -71,17 +71,15 @@
 #define OPERACAKE_ADDRESS_DEFAULT 0x18
 #define OPERACAKE_ADDRESS_INVALID 0xFF
 
+#define OPERACAKE_MAX_BOARDS 8
+
 i2c_bus_t* const oc_bus = &i2c0;
-uint8_t operacake_boards[8] = {
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
-	OPERACAKE_ADDRESS_INVALID,
+
+struct operacake_state {
+	bool present;
 };
+
+struct operacake_state operacake_boards[OPERACAKE_MAX_BOARDS];
 bool allow_gpio_mode = true;
 
 /* read single register */
@@ -105,21 +103,38 @@ void operacake_write_reg(i2c_bus_t* const bus, uint8_t address, uint8_t reg, uin
 }
 
 uint8_t operacake_init(bool allow_gpio) {
-	uint8_t reg, addr, j = 0;
 	/* Find connected operacakes */
-	for(addr=0; addr<8; addr++) {
+	for (int addr = 0; addr < 8; addr++) {
 		operacake_write_reg(oc_bus, addr, OPERACAKE_REG_OUTPUT,
 		                    OPERACAKE_DEFAULT_OUTPUT);
 		operacake_write_reg(oc_bus, addr, OPERACAKE_REG_CONFIG,
 		                    OPERACAKE_CONFIG_ALL_OUTPUT);
-		reg = operacake_read_reg(oc_bus, addr, OPERACAKE_REG_CONFIG);
-		if(reg==OPERACAKE_CONFIG_ALL_OUTPUT)
-			operacake_boards[j++] = addr;
+		uint8_t reg = operacake_read_reg(oc_bus, addr, OPERACAKE_REG_CONFIG);
+
+		operacake_boards[addr].present = (reg == OPERACAKE_CONFIG_ALL_OUTPUT);
 	}
 	allow_gpio_mode = allow_gpio;
 	return 0;
 }
 
+bool operacake_is_board_present(uint8_t address) {
+	if (address >= OPERACAKE_MAX_BOARDS)
+		return false;
+
+	return operacake_boards[address].present;
+}
+
+void operacake_get_boards(uint8_t *addresses) {
+	int count = 0;
+	for (int i = 0; i < OPERACAKE_MAX_BOARDS; i++) {
+		addresses[i] = OPERACAKE_ADDRESS_INVALID;
+	}
+	for (int i = 0; i < OPERACAKE_MAX_BOARDS; i++) {
+		if (operacake_is_board_present(i))
+			addresses[count++] = i;
+	}
+}
+
 uint8_t port_to_pins(uint8_t port) {
 	switch(port) {
 		case OPERACAKE_PA1:
@@ -220,8 +235,14 @@ uint8_t operacake_set_range(uint32_t freq_mhz) {
 	if(i == current_range) {
 		return 1;
 	}
-	
-	operacake_set_ports(operacake_boards[0], ranges[i].portA, ranges[i].portB);
+
+	for (i = 0; i < OPERACAKE_MAX_BOARDS; i++) {
+		if (operacake_is_board_present(i)) {
+			operacake_set_ports(i, ranges[i].portA, ranges[i].portB);
+			break;
+		}
+	}
+
 	current_range = i;
 	return 0;
 }
diff --git a/firmware/common/operacake.h b/firmware/common/operacake.h
index 8d0fba67..c48e9f21 100644
--- a/firmware/common/operacake.h
+++ b/firmware/common/operacake.h
@@ -42,10 +42,9 @@ extern "C"
 
 #define MAX_OPERACAKE_RANGES 8
 
-/* Up to 8 Operacake boards can be used with one HackRF */
-extern uint8_t operacake_boards[8];
-
 uint8_t operacake_init(bool allow_gpio);
+bool operacake_is_board_present(uint8_t address);
+void operacake_get_boards(uint8_t *addresses);
 uint8_t operacake_set_ports(uint8_t address, uint8_t PA, uint8_t PB);
 uint8_t operacake_add_range(uint16_t freq_min, uint16_t freq_max, uint8_t port);
 uint8_t operacake_set_range(uint32_t freq_mhz);
diff --git a/firmware/hackrf_usb/usb_api_operacake.c b/firmware/hackrf_usb/usb_api_operacake.c
index e3dcb580..50619d0a 100644
--- a/firmware/hackrf_usb/usb_api_operacake.c
+++ b/firmware/hackrf_usb/usb_api_operacake.c
@@ -29,7 +29,9 @@ usb_request_status_t usb_vendor_request_operacake_get_boards(
 	usb_endpoint_t* const endpoint, const usb_transfer_stage_t stage)
 {
 	if (stage == USB_TRANSFER_STAGE_SETUP) {
-		usb_transfer_schedule_block(endpoint->in, operacake_boards, 8, NULL, NULL);
+		uint8_t addresses[8];
+		operacake_get_boards(addresses);
+		usb_transfer_schedule_block(endpoint->in, addresses, 8, NULL, NULL);
 		usb_transfer_schedule_ack(endpoint->out);
 	}
 	return USB_REQUEST_STATUS_OK;