FFmpeg for Cedrus on Olimex Lime2 with Armbian Kernel

Hi,
I have compiled the FFmpeg version in "https://github.com/stulluk/FFmpeg-Cedrus" (great job !!) to get h264 hardware encoding on Olinuxino-LIME2-4G A20 board. My goal is to encode in realtime h264 with a low cpu load and to stream video with crtmpserver.
The crtmpserver service runs fine, while FFmpeg exits with the following error:

[cedrus264 @ 0x28cf680] VE Open error.

I entered the following command line:

root@lime2:/etc/campipe# ffmpeg -f v4l2 -s 640x480 -pix_fmt nv12 -i /dev/video0 -pix_fmt nv12 -qp 23 -c:v cedrus264 -threads 0 -b:v 1200k -bufsize 2400k -r 25 -vewait 3600 -an -f matroska - | ffmpeg -i - -c:v copy -f flv -metadata streamName=livestream tcp://0.0.0.0:6666
ffmpeg version git-2015-01-22-f86a076 Copyright (c) 2000-2014 the FFmpeg developers
  built on Oct 22 2016 20:38:02 with gcc 4.9.2 (Debian 4.9.2-10)
  configuration: --prefix=/usr --enable-nonfree --enable-gpl --enable-version3 --enable-vdpau --enable-libx264 --enable-libmp3lame --enable-libpulse --enable-libv4l2 --enable-libtheora --enable-libvorbis --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-libfaac
ffmpeg version git-2015-01-22-f86a076 Copyright (c) 2000-2014 the FFmpeg developers
  built on Oct 22 2016 20:38:02 with gcc 4.9.2 (Debian 4.9.2-10)
  configuration: --prefix=/usr --enable-nonfree --enable-gpl --enable-version3 --enable-vdpau --enable-libx264 --enable-libmp3lame --enable-libpulse --enable-libv4l2 --enable-libtheora --enable-libvorbis --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-libfaac
  libavutil      54.  6.100 / 54.  6.100
  libavcodec     56.  0.101 / 56.  0.101
  libavformat    56.  2.100 / 56.  2.100
  libavdevice    56.  0.100 / 56.  0.100
  libavfilter     5.  0.102 /  5.  0.102
  libswscale      3.  0.100 /  3.  0.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  0.100 / 53.  0.100
  libavutil      54.  6.100 / 54.  6.100
  libavcodec     56.  0.101 / 56.  0.101
  libavformat    56.  2.100 / 56.  2.100
  libavdevice    56.  0.100 / 56.  0.100
  libavfilter     5.  0.102 /  5.  0.102
  libswscale      3.  0.100 /  3.  0.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  0.100 / 53.  0.100
Input #0, video4linux2,v4l2, from '/dev/video0':
  Duration: N/A, start: 1710.222761, bitrate: 73728 kb/s
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 73728 kb/s, 15 fps, 15 tbr, 1000k tbn, 1000k tbc
[cedrus264 @ 0x1b97680] VE Open error.
Output #0, matroska, to 'pipe:':
    Stream #0:0: Video: h264, q=2-31, 128 kb/s, 25 fps
    Metadata:
      encoder         : Lavc56.0.101 cedrus264
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (cedrus264))
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
pipe:: Invalid data found when processing input

Any idea why this is?
Thanks for any infos...

Tommaso