Please refer to the doc link I sent, above says:
It is not 10 sec or 20 sec . You press the reset button first, AND THEN power on the unit and YOU WILL NOT RELEASE the RESET button until you see ..
You have 40 seconds left to select a menu option...
Please select option:
[ Enter ]: Boot Omega2.
[ 0 ]: Start Web recovery mode.
[ 1 ]: Start command line mode.
[ 2 ]: Flash firmware from USB storage. on your screen.
If that does NOT work, the RESET is faulty. There is another method:
In the docs, under the section "STEP4" (as in the above fig)it is given:
You can try that. Basically, you shall apply 3.3V (NOT 5 volt) to GPIO38 pin, which is the 7th pin as marked with WHITE arrow on the image on the right, using a current limiting resistor. 1k is fine. Power ON the unit after the tip of the wire is touching GPIO38.