@ masc & Ilia3101 thanks , yea not too worried about safety right now , you know
Bleeding Edge stuff

The best way to exit crop_rec is to press the play button twice (once to enter in player mode & once to exit player mode)
this will exit to 3x3 (1:1 FHD) without any cam freeze/lockup that needs a battery pull . Then you can enter into crop_rec
again by pressing the 5x zoom .
I was surprised at how long I could record with my Lexar 1066x. ........ got to 2 minutes before eventually stopping it myself.
Will that cool ! I only tested on my slow 90MB/s Sandisk extreme pro , just check on my 32GB Lexar 1066x card .
Holy Cow ! your right , ml is only expecting around 300 frames , I stop at 10GB 3300 frames(2:19 min)
WOW that's continuous

, never thought 3008x1074 @ 23.98fps would be special when 2880x1080 was only good for 20-30 seconds .
Must be because of reducing the head timers 3 & 4 which reducers the over head .
ML reports it takes 92.3MB/s @ 3008x1074 23.98 but in the setting file I see the write speed reported was 75.8MB/s , strange .
Another bonus - HDMI works while recording raw in crop_rec 3k (3008x1074) , check with my HDMI Zacuto EVF .
But you need to enable "Force HDMI to VGA" so that changes the HDMI out put from 1920x1080 to 720x480.
It really very surprising that HDMI works as well as it does in 3k plus recording continuous , that just blow me away

Edit:
For others who may have missed it , 3008x1074 build is available now , details
here