Openbuilds BlackBox Controller - Firmware issue, fails to connect.

Hi,
I have been having some issues with the Blackbox controller. This is my first build and after quite a lot of research I opted for this controller. I wired the controller in and everything was working perfectly, all limit switches worked as designed and all the Steppers worked as the should and I was really happy. Then at the end of some further testing I powered down the unit to have a break. Unfortunately when I went back to the machine I was unable to connect and I got the error "No supported firmware connected, you need a controller with Grbl1.1x ...". I search the forums and documentation and followed all the steps as suggest - trying different Laptops/cables, checking drivers etc. I finally had to give and I called the supplier (ooznest). They were happy to replace the unit and I received the new one and once again I connected without issue. Then after some more test cuts during the day and turning off and on a few times without issue, then later in the day I came back to run a couple more jobs and I get the same message again on the new unit!!
The only thing different I can think of is on the last power down, I accidentally hit the "Reset button" as I switched the power switch to off.
I now have two faulty units to returned but my confidence is now really damaged with using this unit. The supplier are happy to replace and for me to try a 3rd one, but I'm wondering what could I be doing wrong or am I just unlucky in receiving 2 faulty units? I have triple checked the wiring and it is all fine, I'm only using 2 cores (sig & grnd) on the limit switches and the motors are wired fine - everything was working perfect before I shut it down. It just seems to be shutting it down is somehow causing the issue, has anyone else had a similar issue? The supplier did say they have a few unit die like this so perhaps I am not the only one.
Can anyone make any suggestions? Or perhaps I should look for a different controller option, which is a shame as this little unit is very neat.
Any help is most appreciated....thanks

 

Hi Peter,
Thank you for your reply, I have now raised this issue via the contact form you posted.
I was just reading similar posts, which at least it makes me feel that I might not be doing anything wrong.
Just a quick question do you think me hitting the reset button as I switched the on/off switch may have caused the issue? I dont like not knowing what might have caused the problem, so I can avoid it again going forward. Is this a common issue for your experience?

Thanks again for you quick response, it is really appreciated....