I messed up by not checking if correct item was sent to me, and received spiral nails not suitable for flooring...
So, now I am stuck waiting for shipping as i can't find any available supply nearby - Portland (Oregon), which means delaying installation for 5 days at least.
As I don't trust that a regular 16 or 18 gauge trim nail (nail gun type) will hold properly, I was wondering if I could use staples instead?
So far using 2-1/2" cleats on t&g 3/4" solid 4-1/4" maple (standard osb plywood sheeting with quietwalk plus underlayment)

a bit concerned with changing type of fastener, although is "just" for final 3 rows (one more to be top nailed) and if indeed is worth the effort as even a regular stapler won't be able to go all the way to the wall either.
Thanks for the feedback
Phil

Cleats or other fasteners that penetrate through the OSB will not hold any better if they protrude from the bottom surface, unless they penetrate a floor joist. Are you trying to hit the floor joists with at least half of the fasteners? If you are good at carpentry you will be able to pre-drill and drive cleats except on the last row of your planks, or even most of a ripped plank.

the first sentence got me a bit confused: are you saying that does not matter if they are 2-1/2" long? as they could be simply 1-3/4 or 2 inches as long as they go thru the plank and 'bite' at least half way onto the plywood?

I can't see how one can hit the joists - literally would have to memorize the layout and place visual clues along the wall or floor for spacing and location....maybe there is another way to do it, but can't even imagine going thru that. I did indeed map the framing joists in order to be sure to hit them when securing down the sub floor - could not trust the existing nail lines as I was able to see there were a few misses - and then the sub floor/framing was reinforced with 2x6 between joists; so had to take advantage of that. However, once I placed the underlayment, all is gone (markings that is)

the nailgun cleats would not sustain hammering - even taking them out (I had to pull a board and remove the nails, turning it upside down)

Manufacturer (Mirage Flooring) recommends minimum 1-3/4" nails or staples and 2" or 2-1/2" finish nails for the first or last rows, and pre-drilled hand driven finish nails for very last/first against wall.

I still can return the 2-1/2" cleats and replace with a shorter type, but they are penetrating well so far...
Still not trusting on regular nailgun finish nails - even at 2 or 2-1/2 inches to do a proper job.

yes, I am learning as I am a homeowner and this is my first installation ( so please be gentle )

correction - the finish nails are 2-1/2 and the cleats 2 inches

was able to talk with Mirage, and they told me 2 inches it's fine, for both cleats of finish nails or hand-driven nails - just have to use a tighter nailing schedule for last two types - and never to use brad nails....