With respect, RenatoPhoto, your instructions do not match what is on the 5D3 menu lists. For example, there is no file called: raw_rec module (in the crop build for 1.1.3 for example). Other instructions are either not complete or lacking extra info saying which file they pertain to. Possibly because these are 'general' instructions and every build is different? How can anyone know? There is no footnote.
On any walk-through, missing out one setting (or a number) is crucial for some. It can affect the operation of the final outcome and (in my case) cause issues (where I nearly bricked a camera due to lack of instructional detail but with care, guided back to normal)!
I tried everything. Firmware 1.2.3. Firmware 1.1.3 (and I ain't stupid - I can write in C) but sadly, still no 4k for me. Max setting 1920 that is stable. Even the excellent Topic: crop_rec on steroids: 3K, 4K, 1080p48, full-resolution LiveView post video that told me exactly what to did not work. Why? If the instructions were complete then why didn't it work?
I suggest it is because the build used on the Vimeo film is the ONLY one it works on.
Sadly, now there is no way in the world to find the build on the crop_rec_4k.2017Apr29.5D3113 file built on 29. 04. 2017 - seems to be like the holy grail in that it seems to be only one that works the miracles - but nobody can find it! Google can't. I can't. Who is left?
But I do not feel like giving up. Desperate, yes. Frustrated, yes. So please don't delete me and someone, somewhere, for the love of ML, please show me where I can find a detailed (as in something that really, really does work) and gets me recording smoothly.
And if someone can, I will throw £ at the bearer of the best solution that works and put the results on Youtube to help everyone else that really, really wants this to work.