Modify laptop 4k display EDID for Big Sur (run at 48Hz)

modifyedid.py

# Modify laptop 4k panel edid for big sur
# This will make panel running at 48Hz
# Created by xxxzc
# Reference: http://bbs.pcbeta.com/forum.php?mod=viewthread&tid=1866466&highlight=edid
from subprocess import check_output
from base64 import b64encode
from textwrap import wrap

edid = ''
try:
    edid = check_output('ioreg -lw0 | grep -i "IODisplayEDID"',
                            shell=True, encoding='utf-8')
    edid = edid.split('<')[1].split('>')[0]
except Exception:
    edid = input('No edid found, please input it manually: ')

edid = wrap(''.join(filter(str.isalnum, edid)), 2) # convert to 128 bytes

print('Default EDID:', ''.join(edid))

# set refresh rate to 48Hz
if len(edid) == 128: 
    edid[54] = edid[55] = 'a6' # Descriptor 1
elif len(edid) == 256:
    edid[54] = edid[55] = 'a6' # Descriptor 1
    edid[72] = edid[73] = 'a6' # Descriptor 2

data = list(int(x, 16) for x in edid)

csb = 127 # checksum byte
checksum = 256 - sum(data[:csb]) % 256

edid[csb] = hex(checksum)[2:]
print('Patched EDID:', ''.join(edid))

data[csb] = checksum
data = b64encode(bytes(data)).decode('utf-8')
print()
print('You should add following to PciRoot(0x0)/Pci(0x2,0x0):')
print('<key>AAPL00,override-no-connect</key>')
print(f'<data>{data}</data>')

Patch is working for Dell XPS 2020 4k

Patch is working for Dell XPS 2020 4k

Good to hear

Patch is working for Dell XPS 2020 4k

Can you share your lines? I was generated for myself but boot process stuck.

Look into my repo and description.

Look into my repo and description.

Doesn't work for XPS 17 for some reason. My EDID is 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, after patch data looks like this AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBpqYAoPBgRZAwIDYAbuUQAAAYKLkAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgAYECAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAtw== and if I apply this system won't boot - freezes before desktop should appear.

@khmyznikov I updated my script to support 256 bytes EDID , please try this:

patch descriptor 1 and descriptor 2 to 48Hz:

AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBpqYAoPBgRZAwIDYAbuUQAAAYpqYAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgASMCAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAqg==

or patch descriptor 2 only

AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBcucAoPBgRZAwIDYAbuUQAAAYpqYAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgARYCAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAqg==

or patch descriptor 1 only:

AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBpqYAoPBgRZAwIDYAbuUQAAAYKLkAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgAY4CAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAqg==

can you confirm this is your internal panel's EDID? 256 bytes EDID is normally found on external display.

My Device had also 256 bit Edid Try to enable only enable-dpcd-max-link-rate-fix And remove enable-dpcd-max-link-rate 14000000 Also test it with beta build of whatevergreen 1.4.5 from my repo Von meinem iPhone gesendet

…

Am 27.11.2020 um 11:07 schrieb zicong xie ***@***.***>: ***@***.*** commented on this gist. @khmyznikov I updated my script to support 256 bytes EDID , please you try this: AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBpqYAoPBgRZAwIDYAbuUQAAAYpqYAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgASMCAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAqg== or AP///////wBNENYUAAAAAAUeAQS1JRd4CtTGqlMzuiQMUFUAAAABAQEBAQEBAQEBAQEBAQEBpqYAoPBgRZAwIDYAbuUQAAAYKLkAoPBgRZAwIDYAbuUQAAAYAAAA/gA3SlhLOIBMUTE3MFIxAAAAAAACQQMyARIAAAsBCiAgAY4CAw8A4wWAAOYGBQFgYCgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAqg== can you confirm this is your internal panel's EDID? 256 bytes EDID is normally found on external display. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or unsubscribe.

@xxxzc @thefiredragon yes I confirm - it's 256. So with WEG 1.4.5 and with any of three strings from @xxxzc i got same result - screen recognized as 4k and show image, but very very glitchy like every third row of pixels was stolen and image constantly shake and jump. @thefiredragon I used your config and there is already no enable-dpcd-max-link-rate option, only enable-dpcd-max-link-rate-fix.

please provide on my repo your efi, I could take a look

please provide on my repo your efi, I could take a look

It's all your repo copy pasted, just changed override to first one from @xxxzc post

New WEG version fixed this problem