Help is needed! Do not boot netgear readynas duo v2

The tool you found is for Intel based systems and will not work for you.

First, lets be sure you really have a DuoV2.  Netgear used the "V2" designation two different ways.  What we now call a V2 has a part number ending in -200NAS and says "V2" on the front.  If it just says "V2" on a sticker and has a part numnber ending in -100NAS, it's really a V1.

Your NAS is complaining that the root partition is corrupt.  Here is the magic decoder ring:

LED blink behavior for 2 disk systems is three quick blinks of all disk LEDs and the backup LED, followed by an 1s delay, followed by a number of slow blinks.  The number of slow blinks will be the error code.

Current error codes:
1  - Vendor mismatch
2  - No disks detected
3  - Bad contents on root partition of disks
4  - Flash error
5  - Unsupported RAID configuration

A USB recovery is not the fix for this.  An OS re-install is.  I suspect you actually have a V1, which is why the V2 process is not working for you.  Here is the process for a V1:How-do-I-access-the-boot-menu-on-my-ReadyNAS-Duo-NV-NV-X6-or-600