diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
index ee47be4b00..2b646f898f 100644
--- a/supervisor/supervisor.mk
+++ b/supervisor/supervisor.mk
@@ -99,6 +99,10 @@ ifndef USB_MSC_NUM_ENDPOINT_PAIRS
 USB_MSC_NUM_ENDPOINT_PAIRS = 1
 endif
 
+ifndef USB_MSC_MAX_PACKET_SIZE
+USB_MSC_MAX_PACKET_SIZE = 64
+endif
+
 SUPERVISOR_O = $(addprefix $(BUILD)/, $(SRC_SUPERVISOR:.c=.o)) $(BUILD)/autogen_display_resources.o
 
 $(BUILD)/supervisor/shared/translate.o: $(HEADER_BUILD)/qstrdefs.generated.h
@@ -119,6 +123,7 @@ autogen_usb_descriptor.intermediate: ../../tools/gen_usb_descriptor.py Makefile
 	        --devices $(USB_DEVICES)\
 		--hid_devices $(USB_HID_DEVICES)\
 		--msc_num_endpoint_pairs $(USB_MSC_NUM_ENDPOINT_PAIRS)\
+		--msc_max_packet_size $(USB_MSC_MAX_PACKET_SIZE)\
 		--output_c_file $(BUILD)/autogen_usb_descriptor.c\
 		--output_h_file $(BUILD)/genhdr/autogen_usb_descriptor.h
 
diff --git a/tools/gen_usb_descriptor.py b/tools/gen_usb_descriptor.py
index c4ff74d394..d92848c55d 100644
--- a/tools/gen_usb_descriptor.py
+++ b/tools/gen_usb_descriptor.py
@@ -34,6 +34,8 @@ parser.add_argument('--hid_devices', type=lambda l: tuple(l.split(',')), default
                     help='HID devices to include in HID report descriptor')
 parser.add_argument('--msc_num_endpoint_pairs', type=int, default=1,
                     help='Use 1 or 2 endpoint pairs for MSC (1 bidirectional, or 1 input + 1 output (required by SAMD21))')
+parser.add_argument('--msc_max_packet_size', type=int, default=64,
+                    help='Max packet size for MSC')
 parser.add_argument('--output_c_file', type=argparse.FileType('w'), required=True)
 parser.add_argument('--output_h_file', type=argparse.FileType('w'), required=True)
 
@@ -155,14 +157,16 @@ msc_interfaces = [
                 description="MSC in",
                 bEndpointAddress=0x0 | standard.EndpointDescriptor.DIRECTION_IN,
                 bmAttributes=standard.EndpointDescriptor.TYPE_BULK,
-                bInterval=0),
+                bInterval=0,
+                wMaxPacketSize=args.msc_max_packet_size),
             standard.EndpointDescriptor(
                 description="MSC out",
                 # SAMD21 needs to use a separate pair of endpoints for MSC.
                 bEndpointAddress=((0x1 if args.msc_num_endpoint_pairs == 2 else 0x0) |
                                   standard.EndpointDescriptor.DIRECTION_OUT),
                 bmAttributes=standard.EndpointDescriptor.TYPE_BULK,
-                bInterval=0)
+                bInterval=0,
+                wMaxPacketSize=args.msc_max_packet_size)
         ]
     )
 ]