I am trying to now finally install BigSur. After reading up on what I need to change within the OC-config, I think I should be able to boot the installer. Only one problem... If I try to boot my Catalina disk without the "-cdfon", I get no image after the verbose boot. If I boot the Big Sur installer, the same thing happens. I've read that this boot-arg has been broken in 11.0+.
So: Is there a workaround? I think since I have the UHD630 with a 4K screen, I need something like this (it's a HDMI 2.0 enabler IIRC) to get the GUI working... :/. Any experiences over here?
with a 4k display you need -cdfon or (the same) enable-hdmi20 property or you get a black screen.
bigsur broke this patch. wait the new release of whatevergreen
with a 4k display you need -cdfon or (the same) enable-hdmi20 property or you get a black screen.
bigsur broke this patch. wait the new release of whatevergreen
I got a solution now. As I want to help out as many people facing this issue as possible, I will try to explain how this works in more detail, and I've wrote a script which helps you to patch your EDID.
First things first: Big thanks to @thefiredragon, who posted *here* and thus got the concept of how EDID patching works into my head.
What is EDID? EDID stands for "Extended Display Identification Data", and is basically a 128 byte long pack of information the monitor will send to the GPU, in order to negotiate resolution, refresh-rate, and many more things. You can read up on it here, if you're interested: https://en.wikipedia.org/wiki/Extended_Display_Identification_Data
To make the 4K screen work, we need to change the standard refresh-rate of 60Hz (or more, who knows what people got these days) to 48Hz. Don't ask me why, I don't know how that fixes this issue at the moment, but hey - it works. This value consists of a few bits within the 128 bytes, which need hotpatching.
Step 2: WARNING: You should disconnect external monitors from your laptop at this point, to make your life easier.
Now, we want to get the output of 'xrandr --props' into a file, preferredly into a file on the built-in drive's EFI partition for easy access later on.
Code:
[manjaro /]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 20.8M 1 loop /run/miso/sfs/livefs
loop1 7:1 0 570.1M 1 loop /run/miso/sfs/mhwdfs
loop2 7:2 0 1.6G 1 loop /run/miso/sfs/desktopfs
loop3 7:3 0 630.2M 1 loop /run/miso/sfs/rootfs
sda 8:0 1 119.3G 0 disk /run/miso/bootmnt
├─sda1 8:1 1 2.9G 0 part
└─sda2 8:2 1 4M 0 part
nvme0n1 259:0 0 1.8T 0 disk
├─nvme0n1p1 259:1 0 200M 0 part
├─nvme0n1p2 259:2 0 931.4G 0 part
└─nvme0n1p3 259:3 0 931.4G 0 part
[manjaro /]# mount /dev/nvme0n1p1 /mnt
[manjaro /]# cd /mnt
[manjaro mnt]# xrandr --props > display_info.txt
[manjaro mnt]# cd ..
[manjaro /]# umount /dev/nvme0n1p1
I just mounted the EFI of my NVME drive to /mnt, wrote the output into display_info.txt and unmounted again. BTW, I went for a root-terminal here. Just did a sudo /bin/bash, this makes your life easier.
You can transfer it back to OSX however you like to tho. The only important thing is that you get the full output of 'xrandr --props' into a single file with the name 'display_info.txt'.
Step 3:
* Copy my python-script into a file 'patcher.py', just put it on your desktop for now
Python:
import re
import sys
def patch_edid(value):
# Set refresh rate to 48Hz
# EDID structure: https://en.wikipedia.org/wiki/Extended_Display_Identification_Data
edid = value[:108] + 'a6a6' + value[112:]
# Recalculate checksum after change
data = [int(edid[i:i + 2], 16) for i in range(0, len(edid), 2)]
checksum = hex(256 - sum(data[:-1]) % 256)[2:]
# Return value with new checksum
return edid[:-2] + checksum
# Open input file
with open('display_info.txt', 'r') as inp_file:
# Constants needed for processing
begin_marker = 'EDID:' # xrandr starts of EDIDs like this
edid_bytelen = 128 # There are 128 bytes within an EDID
edid_hexlen = edid_bytelen * 2
# Read all file lines
# Strip \t, \n and spaces, since they're not needed for parsing
lines = list(map(lambda x: re.sub(r'[\t\n ]', '', x), inp_file.readlines()))
# Now concat the whole content into one single string
info = ''.join(lines)
# Create a list of EDID occurrences
occurrences = []
# Search all occurrence-indices of EDID beginnings
occ_index = info.find(begin_marker)
while occ_index != -1:
# Substring without the begin-marker
substr_index = occ_index + len(begin_marker)
occurrences.append(info[substr_index:substr_index + edid_hexlen].upper())
# Try to find another occurrence
occ_index = info.find(begin_marker, occ_index + 1)
# No EDIDs available
if len(occurrences) == 0:
print('Could not find any EDIDs, please check your input!')
sys.exit()
# Multiple EDIDs found, prompt for desired one
desired_index = 0
if len(occurrences) > 1:
print('There are multiple EDIDs available, please choose one:')
c = 0
for edid in occurrences:
print(f'[{c}]: {edid[0:30]}...{edid[edid_hexlen - 30:edid_hexlen]}')
c += 1
desired_index = int(input('Your selection: '))
print()
# This will now be the target EDID
target_edid = occurrences[desired_index]
# Patch the value
patched_edid = patch_edid(target_edid)
# Print patch-instructions
print('Patched your EDID!')
print('Please add it to DeviceProperties/Add/PciRoot(0x0)/Pci(0x2,0x0) like this:')
print('Create a new entry: AAPL00,override-no-connect (with type data)')
print('And set the value to:\n')
print(patched_edid.upper())
* Now, make sure your previously created 'display_info.txt' is at the same location as this script - so on your desktop too.
Step 4:
* Run patcher.py with python from the terminal, for example: 'python3.8 patcher.py', depending on your version tho. Just tab the command like this: 'python<tab>'.
* You will get something like this:
Code:
Patched your EDID!
Please add it to DeviceProperties/Add/PciRoot(0x0)/Pci(0x2,0x0) like this:
Create a new entry: AAPL00,override-no-connect (with type data)
And set the value to:
00FFFFFFFFFFFF0006AFEB3100000000101B0104A522137802CEB5A65434B6250E505400000001010101010101010101010101010101A6A600A0F0703E803020350058C110000018000000000000000000000000000000000018000000FE0041554F0A202020202020202020000000FE00423135365A414E30332E31200A00BD
If you get a prompt where you need to choose between different EDIDs, you have multiple monitors connected. Disconnect them or just have a look at the options and find the one corresponding to your monitor (have a look into the display_info.txt and search for familiar names/values). This should almost never happen tho, I built the picker into the script just to make sure.
* Follow the instructions printed. Go to your config.plist and make this entry. Reboot - and you should be good to see the screen of your BigSur installer or already installed disk! Hoping to see a new release of WhateverGreen soon, so we can discard this hack again.
@BlvckBytes do you know if lower resolution like 3360x1890 can work with 60hz refresh rate in Big Sur for 4k laptop?
also, does ResXtreme work in Big Sur?
I actually haven't tried it and - imho - wouldn't recommend to. Why go about the headache of also modifying the resolution when there is next to no noticable difference between 60Hz and 48Hz? It's just a hack for a few weeks max.
But you could play around with it, if you'd like to , would be interesting, gotta say.
I actually haven't tried it and - imho - wouldn't recommend to. Why go about the headache of also modifying the resolution when there is next to no noticable difference between 60Hz and 48Hz? It's just a hack for a few weeks max.
But you could play around with it, if you'd like to , would be interesting, gotta say.
I haven't installed Big Sur as of yet. But id love to see if anybody here has tried lowering resolution a bit or using ResXtreme. And yes its a hack for few weeks, I'm almost certain Acidanthera and the team are working on solution as we speak
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