Same here. Either my unit has no "dead zone" problem...or, it's so minimal, it's not noticeable. Also, sorry for what is about to be a lengthy post...but, I will try to keep it as short as possible, while still putting in all the necessary information.

I'm not going to be one of the 'naysayers', attempting to claim there's no problem...but, I do believe that some units might have said problem. However, while those experiencing the problem want to believe it's a software/firmware problem, I have a theory: I believe it might actually be a hardware problem, related to the throttle mechanism. I have no way of proving my theory, as..again...neither my unit, nor the units belonging to a large number of other people, doesn't have the problem. But, I do have an idea of what, for the units affected, could possibly be causing the problem. I've never taken my NB4 apart (nor do I plan to), so I don't know what, or what specific type, components FlySky is using for the throttle control...but, to explain my theory, I'll use PC keyboards as a comparison.

With PC keyboards, there are two primary types - membrane & mechanical. Both, being 'digital', have only two positions - "on" and "off". The biggest difference (in how they operate) is that, with a membrane keyboard, there is no 'actuation'...the keys only have 'unpressed' & 'pressed' points. For an RC, this is equivalent to the buttons & switches (but not dials) found on a Tx. A mechanical keyboard, on the other hand, has 'actuation', which means the "distance at which the switch needs to depress to register as an input". This is equivalent to the throttle, steering, & dials on a Tx. In a manner of speaking, membrane keyboards sorta-kinda have an actuation point...although, whereas a mechanical switch actuation point is "set" based on the length of the part the key sits on, as well as the hardness/softness of the spring, a membrane keyboard's (so-called) actuation point is determined by how far the membrane is from the curcuit board's contacts, as well as the hardness/softness of the membrane. If the membrane is to close to the circuit board and/or is to soft, this can trigger "false key presses" (often seen as extra letters), which tends to occur mostly on laptops. The same can occur with mechanical switches if the actuation point is too short. At the opposite end of the spectrum, if the actuation point is too long and/or the spring is to hard (mechanical)...or, if the distance between the circuit board & membrane is too far and/or the membrane is too hard (membrane)...this can lead to key presses not being recognized.

In regards to those experiencing the "dead zone" problem on the NB4, what I think is going on is similar to the second point, above, in that the throttle's 'actuation point' is too far. What, specifically, could have caused this, I do not know...but, in assembling the units, I would assume that parts were obtained from multiple sources. If certain parts obtained had one supplier producing them just slightly out of spec, this could, potentially, lead to the problem. Quickly using another comparison (cell phones), I'm sure almost everyone remembers the Samsung Galaxy Note 7 matter. While the great majority of the batteries (in excess of 90%) used in the Note 7 were produced by Samsung, for the initial production run, in order to meet demand, they sourced additional batteries from three other suppliers...and, only some of which were "out of spec". By 'some', I mean VERY few...of the almost 3,000 units reported to have "exploded" (in reality, NONE did, their batteries just went up in smoke), and of the over 500 units checked (from those reporting the problem), only 7 were proven to have problematic batteries. The rest of those with 'problems' were purposely caused by the users, probably in hopes of a lawsuit). Anyway...back to my point. If certain components used in manufacturing the NB4 were produces by multiple suppliers, it is very possible that some of those parts...potentially parts from a single 3rd-party supplier...could have been "out of spec", which, in turn, could be the cause of those units having the "dead zone" problem.

The 'problem' is, unless every unit with the problem were to be tested (to prove whether, or not, it has the problem), and disassembled (to determine, specifically) which part(s) are the cause, it would be impossible to determine which supplier provided the "out of spec" components. When dealing with large components, it can take a large variance to cause a problem...but, when dealing with very small components, a small variance can cause a problem (no different than...say...a large 'adjustment' needing to be made on an X-MAXX, and a very tiny 'adjustment' needing to be made on a Mini-Z, to cause the same amount of "change" on both vehicles). Because many of the parts inside the NB4 are probably small, if the "out of spec" variance on whichever part(s) might be causing the problem is small, it could, potentially, lead to a large "dead zone" problem.

"Hardware" people always want to blame the software, never considering the possibility that it could be the hardware that's at fault...and visa-versa.