stark, I'm not sure that's correct. as kandrews noted, 2K, 3K, and 4K are actually resolution sizes, which would relate to the number of lines on a screen.
raw video is a whole separate issue, and I don't know that we'll be able to sneak that out of existing cams purely with a firmware hack.
Here is yet another explanation.
Unlike other video formats, which are specified in terms of vertical resolution (e.g. 1080p, which is 1920x1080 pixels), digital cinema formats are usually specified in terms of horizontal resolution. As a shorthand, these resolutions are often given in "nK" notation, where n is the multiplier of 1024 such that the horizontal resolution of a corresponding full-aperture, digitized film frame is exactly 1024n pixels. Here the 'K' has a customary, improper meaning: it should be the binary prefix "kibi" (ki) instead.
For instance, a 2K image is 2048 pixels wide, and a 4K image is 4096 pixels wide. Vertical resolutions vary with aspect ratios though; so a 2K image with a HDTV (16:9) aspect ratio is 2048x1152 pixels, while a 2K image with a SDTV or Academy ratio (4:3) is 2048x1536 pixels, and one with a Panavision ratio (2.39:1) would be 2048x856 pixels, and so on. Due to the "nK" notation not corresponding to specific horizontal resolutions per format a 2K image lacking, for example, the typical 35mm film soundtrack space, is only 1828 pixels wide, with vertical resolutions rescaling accordingly. This led to a plethora of motion-picture related video resolutions, which is quite confusing and often redundant with respect to nowadays few projection standards.
All formats designed for digital cinematography are progressive scan, and capture usually occurs at the same 24 frame per second rate established as the standard for 35mm film.
The DCI standard for cinema usually relies on a 1.89:1 aspect ratio, thus defining the maximum container size for 4K as 4096x2160 pixels and for 2K as 2048x1080 pixels  (either 24fps or 48fps). When distributed in the form of a Digital Cinema Package (DCP), content is letterboxed or pillarboxed as appropriate to fit within one of these container formats.