Even if they were more active, this is a pretty specific issue. Hiidra is a very new software still in development, and there's no troubleshooting manual for it. Only
@Aurelio could really know what these error codes might mean, and he's quite a busy lad so he isn't always here.
We could try looking back at your install process. Seeing as it's happened to 2 different Wiis and doesn't seem to be a common issue for other people, it's possible that you've done something differently, or maybe your install media has an issue. Have you re-downloaded the RVLoader files from the github like I suggested before? It's probably worth booting RVLoader into safe mode and running the installer again with fresh files regardless. You get into safe mode by holding L+R+Z when turning the Wii on.
I'm trying to think of more possible things to ask......
Which USB port are you using? Have you tried using the other port?
When you did banner bomb to install the HBC, did you install bootmii as an IOS?
Have you made sure the Wiis are updated to 4.3 firmware?
What region are these Wiis running on? The letter after the firmware version number in the system settings tells the region.
You also didn't answer my question of how many different Wii games you have tried to run. Some specific games have had issues before and needed special patching.
What video output are you using? It probably doesn't matter, but I'm trying to get an idea of what's going on.
Do you have any other microSD cards you can try? Maybe the card you're using is faulty.