dfu-util "Can't claim USB interface" for firmware upgrade of nanovna

Hello All,

Ive been struggling to update the firmware on my NanoVNA on the mac. I'm running a 2012 17" with Sierra (10.12.6). When I put the device into programming mode and run "lsusb" I can see it in the list.

Bus 250 Device 002: ID 05ac:8509 Apple Inc. FaceTime HD Camera (Built-in) Serial: DJHB9P002MDH7JL0

Bus 250 Device 001: ID 0424:2514 SMSC Hub 

Bus 250 Device 003: ID 0a5c:4500 Broadcom Corp. BRCM2070 Hub 

Bus 250 Device 007: ID 05ac:821a Apple Inc. Bluetooth USB Host Controller 

Bus 250 Device 004: ID 174c:55aa ASMedia Technology Inc. AS2105 Serial: 0123456789ABCDEF

Bus 250 Device 005: ID 05ac:0252 Apple Inc. Apple Internal Keyboard / Trackpad 

Bus 253 Device 001: ID 0424:2514 SMSC Hub 

Bus 253 Device 003: ID 0451:8142 Texas Instruments Hub Serial: 110900517D51

Bus 253 Device 005: ID 05ac:026c Apple Inc. Magic Keyboard with Numeric Keypad Serial: F0T71530058HLTRAU

Bus 253 Device 004: ID 0451:8142 Texas Instruments Hub Serial: 710900517D51

======

Bus 253 Device 006: ID 0483:df11 STMicroelectronics STM32 BOOTLOADER Serial: FFFFFFFEFFFF

======

Bus 253 Device 002: ID 05ac:8242 Apple Inc. IR Receiver 

Bus 000 Device 001: ID 1d6b:IPCI Linux Foundation USB 2.0 Bus 

Bus 000 Device 001: ID 1d6b:IPCI Linux Foundation USB 2.0 Bus 

Running dfu-util -l also lists the device

dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.

Copyright 2010-2016 Tormod Volden and Stefan Schmidt

This program is Free Software and has ABSOLUTELY NO WARRANTY

Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

Deducing device DFU version from functional descriptor length

Found Runtime: [05ac:821a] ver=0042, devnum=7, cfg=1, intf=3, path="250-1.1.3", alt=0, name="UNKNOWN", serial="UNKNOWN"

Found DFU: [0483:df11] ver=2200, devnum=6, cfg=1, intf=0, path="253-1.2", alt=1, name="@Option Bytes /0x1FFFF800/01*016 e", serial="FFFFFFFEFFFF"

Found DFU: [0483:df11] ver=2200, devnum=6, cfg=1, intf=0, path="253-1.2", alt=0, name="@Internal Flash /0x08000000/064*0002Kg", serial="FFFFFFFEFFFF"

However when I try to open the device to either backup or burn a new firmware the dfu-util is unable to gain control of the port/interface.

dfu-util -d 0483:* -a 0 -D ch.dfu

Match product ID from file: 0000

Deducing device DFU version from functional descriptor length

Opening DFU capable USB device...

ID 0483:df11

Run-time device DFU version 011a

Claiming USB DFU Interface...

dfu-util: Cannot claim interface

I've tried using sudo and a "root" with the same result. I've also tried specifying the direct address as well and each time its the same message. I can't figure out how to take control of the interface to program the device.

Is it possible? Spent days on this and I'm pulling my hair out. If anyone has advice it would be greatly appreciated. I can plug an Ardunio in and run the IDE and see that board without issue. That uses a specific driver.

Thanks,

Vince