Hobby ComponentsLtd Compatible Pro Mini (3.3V) [Electronics]

Board is not labelled on the back, Mhz isn't marked. Tried 2 different cables and can't upload a sketch, I have checked the cable against 4 other minis that all work.

I bought two of these on the same order. Both were different to each other and neither matched the photo shown on Amazon. Both are 5V Pro Minis, as measured at the VCC pins directly on the microcontroller. Also, an oscilloscope showed the resonator is giving 16MHz to the microcontroller. This would be 8MHz for a 3.3V Pro mini.

I could not manage to upload program using FTDI. However other Arduino Pro Mini 3.3V I had worked fine. Only these ones are bricked :(I also could not figured out what is the type. White squares with indicators 8/16/20 Mhz and 3.3/5 V are not marked. So you do not know is it 8, 16 or 20Mhz :(So unlucky :(

I will be using these to create a Home Automation system. I wanted 3.3V to make integration with the RFM69CW module easier. Very happy.

I had some problems uploading to the boards via FTDI as other reviewers also describes. However it turned out to be a problem with the FTDI driver and not the Pro Mini board itself. When the driver problem was solved all worked fine. So conclusion is that all the boards I received came with an working bootloader and was 3.3V 8 Mhz as described.