My core is not compatible with digispark boards, sorry. Only straight ATTiny device, or via serial bootloader for the 441/841/828/1634/87/167 (addition of serial bootloaders for the other ones is planned for the next release.
I do not currently have any plans to support a USB bootloader - but I've been getting so many inquiries that I'm wondering if I should try to pull in the digispark bootloader and board definitions - I don't have the understanding of USB to adapt it to other supported attinies though.