diff --git a/firmware/hackrf_usb/hackrf_usb.c b/firmware/hackrf_usb/hackrf_usb.c
index ca83abfc..efc74f6b 100644
--- a/firmware/hackrf_usb/hackrf_usb.c
+++ b/firmware/hackrf_usb/hackrf_usb.c
@@ -48,6 +48,50 @@
  
 #include "hackrf-ui.h"
 
+// TODO: Duplicate code/knowledge, copied from /host/libhackrf/src/hackrf.c
+// TODO: Factor this into a shared #include so that firmware can use
+// the same values.
+typedef enum {
+	HACKRF_VENDOR_REQUEST_SET_TRANSCEIVER_MODE = 1,
+	HACKRF_VENDOR_REQUEST_MAX2837_WRITE = 2,
+	HACKRF_VENDOR_REQUEST_MAX2837_READ = 3,
+	HACKRF_VENDOR_REQUEST_SI5351C_WRITE = 4,
+	HACKRF_VENDOR_REQUEST_SI5351C_READ = 5,
+	HACKRF_VENDOR_REQUEST_SAMPLE_RATE_SET = 6,
+	HACKRF_VENDOR_REQUEST_BASEBAND_FILTER_BANDWIDTH_SET = 7,
+	HACKRF_VENDOR_REQUEST_RFFC5071_WRITE = 8,
+	HACKRF_VENDOR_REQUEST_RFFC5071_READ = 9,
+	HACKRF_VENDOR_REQUEST_SPIFLASH_ERASE = 10,
+	HACKRF_VENDOR_REQUEST_SPIFLASH_WRITE = 11,
+	HACKRF_VENDOR_REQUEST_SPIFLASH_READ = 12,
+	_HACKRF_VENDOR_REQUEST_WRITE_CPLD = 13,
+	HACKRF_VENDOR_REQUEST_BOARD_ID_READ = 14,
+	HACKRF_VENDOR_REQUEST_VERSION_STRING_READ = 15,
+	HACKRF_VENDOR_REQUEST_SET_FREQ = 16,
+	HACKRF_VENDOR_REQUEST_AMP_ENABLE = 17,
+	HACKRF_VENDOR_REQUEST_BOARD_PARTID_SERIALNO_READ = 18,
+	HACKRF_VENDOR_REQUEST_SET_LNA_GAIN = 19,
+	HACKRF_VENDOR_REQUEST_SET_VGA_GAIN = 20,
+	HACKRF_VENDOR_REQUEST_SET_TXVGA_GAIN = 21,
+	_HACKRF_VENDOR_REQUEST_SET_IF_FREQ = 22,
+	HACKRF_VENDOR_REQUEST_ANTENNA_ENABLE = 23,
+	HACKRF_VENDOR_REQUEST_SET_FREQ_EXPLICIT = 24,
+	HACKRF_VENDOR_REQUEST_USB_WCID_VENDOR_REQ = 25,
+	HACKRF_VENDOR_REQUEST_INIT_SWEEP = 26,
+	HACKRF_VENDOR_REQUEST_OPERACAKE_GET_BOARDS = 27,
+	HACKRF_VENDOR_REQUEST_OPERACAKE_SET_PORTS = 28,
+	HACKRF_VENDOR_REQUEST_SET_HW_SYNC_MODE = 29,
+	HACKRF_VENDOR_REQUEST_RESET = 30,
+	HACKRF_VENDOR_REQUEST_OPERACAKE_SET_RANGES = 31,
+	HACKRF_VENDOR_REQUEST_CLKOUT_ENABLE = 32,
+	HACKRF_VENDOR_REQUEST_SPIFLASH_STATUS = 33,
+	HACKRF_VENDOR_REQUEST_SPIFLASH_CLEAR_STATUS = 34,
+	HACKRF_VENDOR_REQUEST_OPERACAKE_GPIO_TEST = 35,
+
+	/* Update to be the next integer after the highest-numbered request. */
+	_HACKRF_VENDOR_REQUEST_ARRAY_SIZE	
+} hackrf_vendor_request;
+
 static usb_request_handler_fn vendor_request_handler[] = {
 	NULL,
 	usb_vendor_request_set_transceiver_mode,