Problems with dfu-utils flashing tomu on MacOS - dfu-util: Cannot set alternate interface

[ff6347]

Hi, thank you for this project. I tried to follow the instructions to flash a tomu with your firmware but had no look with that.

I'm running

• MacOS 10.14.6
• dfu-util 0.9

The first error I'm running into is uploading the binary to the tomu:

 $ dfu-util -d 1209:70b1 -D u2f-TOMU.bin

> 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/
> 
> dfu-util: Invalid DFU suffix signature
> dfu-util: A valid DFU suffix will be required in a future dfu-util release!!!
> Opening DFU capable USB device...
> ID 1209:70b1
> Run-time device DFU version 0101
> Claiming USB DFU Interface...
> Setting Alternate Setting #0 ...
> dfu-util: Cannot set alternate interface

I tried with the prebuilt binary and a self compiled one and I get the same error.
Any hints what might be wrong?