1) Yeah ok so at least I understood that part. Though that isn't of much help if the issue isn't related to any potential fixes I mentioned.

2) the `bummm' sound is like a vibration sound? To me it really sounds like your device is somehow seriously messed up if it cannot even enter into R&D mode properly.

Now my question at this point is that when you flashed the device, which eMMC and fiasco image did you use? did those successfully flash? what was your host OS at the time when you used to flash it?