My laptop is dell 7380, with CPU i5-7200U, HD620, platform-id is 59160000.
I was having exactly the same issue, however, I solved the issue after many tries.
Maybe UHD630 is different from HD620, but I wrote here to provide you some information for reference. (I tried only on 10.14.1)
try 1:
Operation:
official whatevergreen (1.2.4)+ applebacklightfixup.kext + config.plist & PNLF.aml found from
https://github.com/RehabMan/OS-X-Clover-Laptop-Config
Observations:
- Internal screen is black for 3 minutes, afterwards, the screen and brightness control works good, even after sleep and wakeup.
- Meanwhile, external screen works great all the time, right after boot.
try 2:
I googled and found this thread, so i changed to:
headkaze's whatevergreen (1.2.4b1, #191) + PNLF-debug.aml (I added the platform id 0x1659 to this aml in the coffee lake platform id judgement area to make the new debug code work on my HD620) + SSDT-RMDT.aml + igfxcflbklt=wrap
Observations:
- Internal screen is on right after boot (sounds good), but internal screen is black after sleep (it's bad)
- External is still fine.
I also tried many ways, such as adding config.plist/Devices/framebuffer-* options, or injecting EDID with 0x9c7c, or use modifed whatevergreen with option igfxcfbklt=freq, etc... There was no luck.
try 3 (finally...) :
I restored everything with the operations in try 1, and this time I also add SSDT-RMCF.aml. and set LMAX to 0x0D88.
Now the internal and external screen works just great!
Why the number is 0x0D88?
Because I followed a thread by rehabman (I can't find the URL right now) to find my PWMAX:
- install hex fiend, run command:
open -a "Hex Fiend" /System/Library/Extensions/AppleIntelKBLGraphicsFramebuffer.kext/Contents/MacOS/AppleIntelKBLGraphicsFramebuffer
- search for your platform id HEX, e.g. 00001659, and use the number around offset 32 (maybe)
- my HEX in 10.14.1 is 00001659 4C890DAA 9408004D 89CEB201 8815A794 0800880D A2940800 880D9D94 0800880D 98940800 C7058F94 08000000 20028905 ...., so I just used 0x0D88
BTW, in 10.14.0, the hex code for 00001659 is different in Framebuffer...
In conclusion , I guess some laptops just show the lowest brightness level (and the lowest brightness level is just black screen, caused by kext or aml) right after the boot. And after 3 minutes, something happend (maybe a sleep/wakeup, or sth in the system), and the brightness level just rose from the lowest level to a higher one, so the screen is back.