I had problems too - SHORT: all about USB-hub or PC's root-hub and extension cables +Luck.
My ebay items were going under the name "Digispark Kickstarter ATTINY85 Arduino Micro USB Development Board" and naturally it came with no Digispark-(c)-right infringing markings from China. I kept my fingers crossed that my items would at least be AVRisp-programable..
So in high hopes I plugged in my China import into my trusty USB HUB2.0(which I always use at least as a current limiter) – after testing it first on a powerbank (>5secs blinky-blink) .. checked for enumeration (which it did-but no driver yet) .. installed the DPinst.exe drivers.. and then kept getting messages like >>device failed to enumerate<<, etc. - the list of my failures:
determined directly plugged into a PC's USB root-hub rigged/minimalistic usb devices do not enumerate at all (all 0s)
with a certain USBAmale-to-USBAfemale extension cable with plastic-encasing(female side) the USBA device’s was not allowed to go "in" probably just for some millimeters to short.. the Data-lamella do not connect correct – just power's okay (blinky-blink) .. but no Windows device-recognition .. No-No!
AND reminding the FTDI black-listing dilemma I used PCs without out the drivers still – using the good old “USBview.exe” program to check on the enumeration (on all my available device the same .. previously plugged into my driver-enable PC or just into an “out of the fab”-one
so no mis-configuration of the bootloader through a >possibly mallign< Digispark clone dis-configurator (as I was thinking the FTDI schemes .. of course FTDI only did it to protect their name X-) – to stop getting accused for faulty devices coming from cheap chinese fake or clone-producers)
* EVEN tried to deinstall the Drivers with DPinst.exe /D .. which gave me .. Yes .. yet again “Drivers all installed properly!”..
.. and IN THE END .. I just went back to my old, initial “USB HUB-behind root-hub” configuration .. and Abra-ca-Zang .. the device just enumerated and registered as “Digispark Bootloader” (windows device manager under libusb-win32 Usb Devices)
and all went okay - reprogramming with the Arduino IDE - NO FUZZ!
.. The !very same! config I was using on my “first testings” (minus some fair time and headaches of debugging)
So my advice .. always do a Basic-Test on a USB Powerbank, USE an USB-Hub, check your cables - use ones you trusted before! – try as many options as you (may) have .. and use the tools at your hand .. down to PC-progs or an logic-analyzer or an Beagle USB / protocol analyer to check where the problem may be.. trace back your tracks and even retry..
There may be a suprise for you at the end of the rainbow!