Cubieboard2 and Monitor

Hi all,

I'm trying to use a BENQ FP767 monitor with a Cubieboard2 using Legacy Server Jessie 5.25 image.

The system is composed: Cubieboard -> HDMI to VGA converter -> Monitor.

The bootloader works perfectly and I can see the boot phases in monitor which is synched to:

  1280x1024

   H.F : 79 KHz

   V.F : 75 KHz

When Linux start the monitor frequencies change and chars are almost unreadable:

   1280x1024

   H.F : 67 KHz

   V.F : 59.7 KHz

I've tried to change boot.cmd monitor settings from:

​ 

  setenv disp_mode "1920x1080p60"

to

​  setenv disp_mode "1024x1080p75"

end compile changes with 

# mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr
root@cubieboard2:/boot# mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr
Image Name:
Created:      Fri Feb 17 08:59:38 2017
Image Type:   ARM Linux Script (uncompressed)
Data Size:    2615 Bytes = 2.55 kB = 0.00 MB
Load Address: 00000000
Entry Point:  00000000
Contents:
   Image 0: 2607 Bytes = 2.55 kB = 0.00 MB

After the "reboot now" command bootload is yet OK but monitor don't show nothing.

Is possible to avoid to change monitor settings entering in Linux from bootloader ?

I've mistake setenv disp_mode configuration ?

Best Regards,
​Silverio Diquigiovanni