If you bought a genuine RVT Writer you would not have needed the firmware: https://www.ebay.co.uk/itm/Wii-Deve...428434?hash=item4b41ad5f92:g:YgkAAOSwXrBa1P8Q But it sounds like you have already purchased an NR Writer now.
Pretty sure you arent just going to flash a stock drive with the firmware. For the RVT, you need to hack the updater to bypass model checks etc. I would imagine the NR writer/SW-9501 is exactly the same. Honestly, from this post and your NR reader post - you seem to like to pay over the odds for things lol