I’ve seen something in bootargs in kvim.h
I will replace
“root=LABEL=ROOTFS rootflags=data=writeback rw logo=osd1,loaded,0x3d800000,1080p60hz,full hdmimode=1080p60hz m_bpp=32 dmfc=3 vout=hdmi cvbsmode=576cvbs console=ttyS0,115200n8 console=tty0 no_console_suspend consoleblank=0 fsck.repair=yes net.ifnames=0\0” \
with
“root=/dev/mmcblk0p1 rootflags=data=writeback rw rootwait console=ttyAML0,115200 console=tty0 earlyprintk=aml-uart,0xc81004c0 fsck.repair=yes governor=ondemand no_console_suspend elevator=noop\0” \
and test…
edit : fail as /dev/mmcblk0p1 does not exist dixit uboot (as opposed to /dev/mmcblk1p01 !)
finally : this did the trick
"root=LABEL=ROOTFS rootflags=data=writeback rw rootwait console=ttyAML0,115200n8 console=tty0 no_console_suspend consoleblank=0 logo=osd1,loaded,0x3d800000,1080p60hz,full hdmimode=1080p60hz m_bpp=32 dmfc=3 vout=hdmi cvbsmode=576cvbs fsck.repair=yes net.ifnames=0\0" \
now I have a xenial base 16.04.3 booting on top of 4.12-rc6 (from numbqq) 
, serial console is working, as well as ethernet (sudo apt-get dist-upgrade went ok);
login prompt appear on hdmi monitor, but usb keyboard not working (known) so cannot log in that way !