There are two connectors on the board which are needed for unbricking.
1. The serial port - is used for access to the bootloader.
An adapter with 3.3V voltage (mostly called 3.3V TTL) levels is needed. It can be either USB/TTL or Serial/TTL.

Never connect a PC's serial port directly to the NAS!
Connect Rx of the NAS with Tx of the adapter and vice versa.
2. The JTAG connector - is needed if the bootloader has been erased or overwritten and does not respond any more
A special adapter JTAG adapter is needed. Either an adapter for the LPT port or an FTDI FT232R chip based one for the USB port may be used.
A description can be found at the
wiki This is a description for the Raidsonic NAS2000 but it should be the same for the MVIXBox.
At the
openGemini Wiki there is a very good description of the bootloader and the boot process.
The bootloader can also be found for
download there.
Serial Port - [attach]230[/attach] JTAG Port - [attach]231[/attach]
HWguru