The vt(4) resolution is always 640x480

[alphachi]

The laptop is ThinkPad X250 (Broadwell GPU) and the LCD resolution is
1366x768. I have set booting from UEFI only and disabled CSM. The whole
disk is encrypted by GELI except /boot/.

On 10.2-STABLE, the LCD resolution can be recognized rightly without any
configure in /boot/loader.conf. The information about this in dmesg is:
...
FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
VT(efifb): resolution 1366x768
CPU: Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz (2194.96-MHz K8-class CPU)
...

But when the system is upgraded to 10.3-BETA2, the only resolution is
640x480 whether console or Xorg. The information about this in dmesg is:
...
FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
VT(efifb): resolution 640x480
CPU: Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz (2194.96-MHz K8-class CPU)
...

I try to write the new EFI file using:
dd if=/boot/boot1.efifat of=/dev/ada0p1
or add something in /boot/loader.conf like:
kern.vt.fb.default_mode="1366x768"
No effect.

How to deal this? Thanks!