It seems not all pins are wired, so the microSD extension failed to boot our RPi2/3/Zero boards. It should be written on the extender description.
Response from Tall Dog | May 17, 2017
First, thanks for taking the time to leave a review here. I'm sorry to hear that the kit isn't working out for you.
If there's any problems with the parts themselves, I want to know about it so I can make things right. Even if you're just unhappy with the purchase, I'd still really like to provide you with a refund. I take customer satisfaction to heart.
Perhaps, after getting more info from you, I might even be able to improve the kit to better suit your needs.
Please contact me ASAP at email@example.com so that we can get the ball rolling.
The pictures on the website show the unit with the carrier rails removed and with headers installed, and show the kit as including 4 40-pin headers. I ordered the unit assembled and left the selection as "leave carrier rails on." When I received the unit it the packing slip listed the 4 headers but the unit did not have headers on it nor were there loose headers in the package. I thought that an error had been made and the headers had not been put on, but when I went back to the web page and looked at the other choice, I saw that it was "remove carrier rails and install headers" which implies that the default which I had left unchanged when I ordered meant rails but no headers. It would be clearer if the default option was "leave carrier rails on and do not install or include headers" and if the packing slip with the package did not list headers which are in the photos on the web page but are not in the package.
Response from Tall Dog | March 15, 2017
The buyer and I discussed this situation and were able to reach a resolution. The order was missing the extra pin headers which would typically be included with an order of this type. I offered to send additional pin headers to the buyer at no cost, but they declined this offer. I also sent an extra free parts kit to this buyer to compensate them for the trouble and thank them for taking the time to leave detailed feedback.