Hi,
Which version of the littlewire did you used?
Pre v1.2 versions of the littlewire don't have v-usb based (micronucleus) bootloader. They have an UART based one.
Also,
For the firmware side I believe there is not too much difference in terms of the V-USB between the micronucleus,Digispark libraries and the littlewire.
Lastly,
Which OS are you using?
Best,
ihsan.