Dell Precision 7510 4k display bugs

Hello.

I faced bugs in 1.14.4 BIOS firmware for Precision 7510.

1. Switchable graphics enabled.

Laptop always behave same way. It boot normally, but there is no image on 4K laptop's display (black screen, no backlight) while firmware booting. HDMI functions only if the laptop cover is closed.

Laptop's 4k display switches on after linux kernel started loading. So it works normally with 4k resolution in Linux OS. It always work in linux.

2. Switchable graphics disabled.

Laptop's display functions occasionally since the start of the BIOS firmware loading. So sometimes i can go to BIOS settings / operate boot sequence and so on.
If screen does not functions immediately after the laptop turned on, then there is no image in Linux and there is no image via hdmi (coolers are operate, keyboard is highlighted).

If screen operates it operates normally in 4k resolution in Linux.
If screen operates it usally does not funtions after reboot.

I guess that this behavior is caused by incorrect handling of second mode from panel's EDID by BIOS firmware. 

Configuration:

• Intel core i7-6820HQ
• nVidia Quadro M2000M
• Sharp 4k panel LQ156D1JW02

Decoded panel EDID:

EDID version: 1.4
Digital display
8 bits per primary color channel
DisplayPort interface
Maximum image size: 35 cm x 19 cm
Gamma: 2.20
Supported color formats: RGB 4:4:4, YCrCb 4:4:4
Default (sRGB) color space is primary color space
First detailed timing is preferred timing
Established timings supported:
Standard timings supported:
Detailed mode: Clock 533.250 MHz, 346 mm x 194 mm
               3840 3888 3920 4000 hborder 0
               2160 2163 2168 2222 vborder 0
               -hsync -vsync 
Detailed mode: Clock 533.250 MHz, 0 mm x 0 mm
               3840 3888 3920 4000 hborder 0
               2160 2163 2168 2776 vborder 0
               -hsync -vsync analog composite 
ASCII string: T41VN
Manufacturer-specified data, tag 0
Checksum: 0x74 (valid)

EDID in hex:

00ffffffffffff004d1030140000000031180104a52313780edf50a35435b5260f5054000000010101010101010101010101010101014dd000a0f0703e80302035005ac2100000184dd000a0f070688230203500000000000000000000fe00543431564e804c513135364431000000000002010323001100000b010a20200074