Lenovo ThinkPad T420 with UEFI Only

[rolitab]

Hi everyone. I'm using my thinkpad t420 as hackintosh since 2014, thanks tluck! Is there any chance to make a safe update from 10.10.4 to 10.13? And should I do it? Yosemite works really good ans stable, but I want to check new OS by Apple. Really appreciate your advices!

[vusun123]

Hi everyone. I'm using my thinkpad t420 as hackintosh since 2014, thanks tluck! Is there any chance to make a safe update from 10.10.4 to 10.13? And should I do it? Yosemite works really good ans stable, but I want to check new OS by Apple. Really appreciate your advices!

You would really want to reinstall and use Apple's Time Machine to restore apps/personal files

[tluck]

@rolitab

 

it should update just like a real mac....  but if you can make a backup - do that

also make a usb installer 

update your kexts and clover before updating to to high sierra.

[rolitab]

@rolitab

 

it should update just like a real mac....  but if you can make a backup - do that

also make a usb installer 

update your kexts and clover before updating to to high sierra.

 

thanks a lot for your reply. do you recommend updating? is it also stable like yosemite? i see that some people in this topic have issues, but my setup is 100% stable right now.

[chris1111]

@rolitab

Me what I do on my HP ProBook before each update System is to do everything on an external SSD and I make sure everything works and after I know that I can do it

[rolitab]

I've just updated to 10.13.3... Everything seems to be fine, except graphics issue - when I watch video on youtube some horizontal lines apper, sometimes green, sometimes violet.

I've updated Clover on ESP manually, then run _kext-install.command, renamed config.plist to fit my display, then updated like a real mac. Did I miss something?

[rolitab]

I've just updated to 10.13.3... Everything seems to be fine, except graphics issue - when I watch video on youtube some horizontal lines apper, sometimes green, sometimes violet.

I've updated Clover on ESP manually, then run _kext-install.command, renamed config.plist to fit my display, then updated like a real mac. Did I miss something?

 

Now I can tell more. After several hours of using High Sierra I can tell that it was a big mistake to update from 100% working Yosemite. I got full system freezes 3 times, like on windows. Apple Mail lost all my Mail. Photos.app lost all faces and started scan again, which don't seem too end ever. Graphics artifacts - horizontal lines sometimes appear.

Maybe I should do clean install to avoid all these issues, I don't really know. But if anyone wants to update like I did — I would recommend against it.

[SabithaSuki]

So after finishing the install of Mavericks, and transfering over the kexts, I still cant get the trackpad or built in keyboard working. Is there a Mavericks driver for that I can download, or a step I am missing?

[Somez]

Now I can tell more. After several hours of using High Sierra I can tell that it was a big mistake to update from 100% working Yosemite. I got full system freezes 3 times, like on windows. Apple Mail lost all my Mail. Photos.app lost all faces and started scan again, which don't seem too end ever. Graphics artifacts - horizontal lines sometimes appear.

Maybe I should do clean install to avoid all these issues, I don't really know. But if anyone wants to update like I did — I would recommend against it.

 

I feel your pain, I'm also having system freezes (mouse can move though) since switching to High Sierra from Sierra.

Those irritating colored lines are much better (still not perfect, but better) if you try the BIOS from this post.

[tluck]

@somez @rolitab - sorry to hear you are having troubles...

 

on the freeze... i wonder if you are getting the buffer hang issue that often plagues HD 3000.

run this on the command line to see if these dreaded SYNC messages are the log:

log show --predicate 'processImagePath contains "kernel" ' | grep BRSYNC

colored lines?

across the entire screen or just in the browser?

do you have a matching DisplayOverride for your LCD? 

are you injecting the custom EDID?

 

perhaps you could test using the DSDT with an embedded EDID and then not have clover inject graphics?

[Somez]

@somez @rolitab - sorry to hear you are having troubles...

 

on the freeze... i wonder if you are getting the buffer hang issue that often plagues HD 3000.

run this on the command line to see if these dreaded SYNC messages are the log:

log show --predicate 'processImagePath contains "kernel" ' | grep BRSYNC

colored lines?

across the entire screen or just in the browser?

do you have a matching DisplayOverride for your LCD? 

are you injecting the custom EDID?

 

perhaps you could test using the DSDT with an embedded EDID and then not have clover inject graphics?

 

Hi tluck,

 

Here is the output of that log (pasted only the 1st few lines, but got a lot of these between Jan 30 and 31, but nothing after this period):

 

2018-01-07 09:02:01.500484+0100 0x3d6      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:36:59.423371+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:04.428958+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:09.432905+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:14.433090+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:19.438802+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:20.681101+0100 0x4a4      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:24.439515+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-31 16:31:21.174853+0100 0x51c      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-31 16:31:26.190918+0100 0x139d2    Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

 

What does this log mean?

 

Regarding the colored lines. On my machine it only appears inside the area of YouTube videos both in full screen and in windowed mode. It was quite frequent right after upgrading to High Sierra but then I installed a few updates and rebooted a few times and the colored lines went away. I wasn't able to identify any pattern, but I've experienced this phenomenon since El Capitan and it always gotten better as time passed

 

Display override: I installed as per your guide.

Custom EDID: I cannot tell. What is this?

 

Thanks for your help.

Just had another of this freeze. This time it took approx. 45 mins but earlier it took like 10.

Also, when the machine freezes, that means I can still move the cursor around but nothing happens. I wonder if the system in the background is still functioning and only the screen if frozen.

[SabithaSuki]

On an additional note, I can't use the trackpad or build in keyboard whenever I try to re-install as well as on the HDD. It works in clover, but no the os. Is this normal, or am I doing something wrong?

[tluck]

So after finishing the install of Mavericks, and transfering over the kexts, I still cant get the trackpad or built in keyboard working. Is there a Mavericks driver for that I can download, or a step I am missing?

 

well it has been a really long time - 4 years -  since i did anything with Mavericks - i wont ask why?!  but here is a old zip with kexts that may work with that OS.

Hi tluck,

 

Here is the output of that log (pasted only the 1st few lines, but got a lot of these between Jan 30 and 31, but nothing after this period):

 

2018-01-07 09:02:01.500484+0100 0x3d6      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:36:59.423371+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:04.428958+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:09.432905+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:14.433090+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:19.438802+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:20.681101+0100 0x4a4      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-30 21:37:24.439515+0100 0xdf56     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-31 16:31:21.174853+0100 0x51c      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

2018-01-31 16:31:26.190918+0100 0x139d2    Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

 

What does this log mean?

 

Regarding the colored lines. On my machine it only appears inside the area of YouTube videos both in full screen and in windowed mode. It was quite frequent right after upgrading to High Sierra but then I installed a few updates and rebooted a few times and the colored lines went away. I wasn't able to identify any pattern, but I've experienced this phenomenon since El Capitan and it always gotten better as time passed

 

Display override: I installed as per your guide.

Custom EDID: I cannot tell. What is this?

 

Thanks for your help.

Just had another of this freeze. This time it took approx. 45 mins but earlier it took like 10.

Also, when the machine freezes, that means I can still move the cursor around but nothing happens. I wonder if the system in the background is still functioning and only the screen if frozen.

 

 

so if you get BRSYNC etc in your kernel log, you are experiencing the HD 3000 Buffer hangs - which freezes everything and generally means a hard reset to reboot. 

 

perhaps try use the the DSDT called dsdt.edid.aml or dsdt.edid-hs.aml (for hs=heatstep) - which is the one i am using.

the override will match the EDID in config.1600x900.plist and one of the DisplayOverrides etc.

 

so copy replace the current dsdt.aml file in ESP ie copy dsdt.edid-hs.aml to /Volumes/ESP/CLOVER/ACPI/patched/dsdt.aml 

 

run this to clear out logs: sudo log erase --all

and then reboot

T420_UEFI-Clover-b2747_10.8.5_10.9.4_2014-06-30.zip

[Somez]

well it has been a really long time - 4 years -  since i did anything with Mavericks - i wont ask why?!  but here is a old zip with kexts that may work with that OS.

 

 

so if you get BRSYNC etc in your kernel log, you are experiencing the HD 3000 Buffer hangs - which freezes everything and generally means a hard reset to reboot. 

 

perhaps try use the the DSDT called dsdt.edid.aml or dsdt.edid-hs.aml (for hs=heatstep) - which is the one i am using.

the override will match the EDID in config.1600x900.plist and one of the DisplayOverrides etc.

 

so copy replace the current dsdt.aml file in ESP ie copy dsdt.edid-hs.aml to /Volumes/ESP/CLOVER/ACPI/patched/dsdt.aml 

 

run this to clear out logs: sudo log erase --all

and then reboot

 

Thank you tluck, I really appreciate your help.

I've copied the heatstep version to the ESP and will report back how it works. I just hope I'll not forget about the next time I'm updating the package to a newer version

[SabithaSuki]

well it has been a really long time - 4 years -  since i did anything with Mavericks - i wont ask why?!  but here is a old zip with kexts that may work with that OS.

Thank you SO Much. A quick whip of kext utility did this wonders!

[Somez]

Thank you tluck, I really appreciate your help.

I've copied the heatstep version to the ESP and will report back how it works. I just hope I'll not forget about the next time I'm updating the package to a newer version

 

Well, I got the freeze and the BRYSNC messages in the log again

What could be the problem?

 

I mounted the EFI partition as usual (and as the guide says), then copied the file as instructed:

 

sudo mkdir /Volumes/ESP

sudo mount -t msdos /dev/disk0s1 /Volumes/ESP

cp -a /Volumes/ESP/EFI/CLOVER/ACPI/dsdt.edid-hs.aml /Volumes/ESP/EFI/CLOVER/ACPI/patched/dsdt.aml

 

then cleared the log

 

sudo log erase --all

 

Thank you.

[tluck]

@somez - i would be curious about the native EDID... maybe it will work for you. so maybe dont inject the custom EDID and revert to old DSDT.aml

 

so lets see what your native EDID looks like.

edit config.plist 

set EDID inject false

set IntelGFX inject true.

use regular or HeatStep DSDT.aml

[rolitab]

@somez @rolitab - sorry to hear you are having troubles...

 

on the freeze... i wonder if you are getting the buffer hang issue that often plagues HD 3000.

run this on the command line to see if these dreaded SYNC messages are the log:

log show --predicate 'processImagePath contains "kernel" ' | grep BRSYNC

colored lines?

across the entire screen or just in the browser?

do you have a matching DisplayOverride for your LCD? 

are you injecting the custom EDID?

 

perhaps you could test using the DSDT with an embedded EDID and then not have clover inject graphics?

 

Thanks for your help! Here is my output:

2018-02-04 02:42:00.705849+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:01.285151+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:05.729561+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:10.743586+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:15.764228+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:20.767004+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:20.784141+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:25.804752+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:30.821526+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:35.839232+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:40.861607+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:41.198522+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:45.881439+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:50.898912+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:42:55.919069+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:00.923077+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:05.930683+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:10.938015+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:15.954397+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:20.959441+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:25.976726+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:30.996862+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:36.002766+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:41.030741+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:41.153090+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:46.169888+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:46.262618+0300 0x12e3     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:51.180627+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:43:56.190148+0300 0x545      Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0
2018-02-04 02:44:00.409486+0300 0x7de9     Default     0x0                  0      0    kernel: (AppleIntelHD3000Graphics)     BRSYNC: (0x22040) = 0x0

In my case horizontal lines appear inside browser window, only on the video (youtube, vimeo, others).

I didn't injected custom id, I have DisplayOverride for my LCD. But I also use external display, and these lines appear on both of them.

 

perhaps you could test using the DSDT with an embedded EDID and then not have clover inject graphics?

 

Can you please give more detail how should I do it?

 

Of couse the biggest issue is system freezes. I was thinking that these freezes happen because of system being idle at that time... Then I tried to play music all the time - and what I've found out is that music keeps playing, I can move mouse pointer, but that's it - I cannot do anything else and I have to reboot.

 

Also I made a backup of my Yosemite installation and backup of its ESP... But for some reason I cannot boot from it. This backup is on external USB HDD. I restored ESP from the backup, then I try to boot from it, I see progress bar and at some point laptop just restarts... I made a backup with SuperDuper, also made it bootable. I will appreciate any help on it. I was thinking that this backup will help, but just I cannot understand what's happening.

[Horban]

I have installed this compilation but a solution for patching kext for DW1520 (BCM943224HMS):

 

" Add this to config.plist:

 

<dict>

<key>Comment</key>

<string>DW1520 Whitelist Patch (MBP8,1)</string>

<key>Disabled</key>

<false/>

<key>Find</key>

<data>

TWFjLTJFNkZBQjk2NTY2RkU1OEM=

</data>

<key>Name</key>

<string>AirPortBrcm4360</string>

<key>Replace</key>

<data>

TWFjLTk0MjQ1QjM2NDBDOTFDODE=

</data>

</dict>"

 

It doesn't work eve having installed the FakePCIID and Brcm kext. Earlier compilation from November 2017 was worked, this from January 2018 don't work.

 

Also I'm trying dual boot macOS with Windows 10 Pro but after installing Windows it doesn't work...

 

I have SSD 120Gbb with partition table:

EFI on disk0s1

macOS on disk0s2

Windows on disk0s3

 

macOS was first installed with spilted disk, then installed Clover on EFI partition and finally Windows on third partition which corrupt Clover boot, it replaces to Windows boot EFI..

[tluck]

@somez and @rolitab

 

the 1600x900 config has an EDID injected as alternative. There are DSDT files included with this matching EDID.

you can turn off this custom EDID (in Clover option menu) or create an alternative config.plist file to test the native EDID from your BIOS/LCD. 

 

Also you try the various Aptio efi drivers  - try AptIoFix vs AptIoFix2 vs AptioFix3 to see how each behaves for you.

 

The EDID embedded in the config.1600x900.plist and the dsdt.edid.aml files - were designed to fix problems with the AUO vendor that come stock in many T420.

So if you have an LGD (or non-AUO) display then you may not need this fix. Sometime in the last 2 years, I replaced my LCD with a glossy $40 LGD option - which is looks and works 10x better than the poor AUO version. So I am going to run without the custom EDID injected to validate.

Edited February 6, 2018 by tluck

[tluck]

I have installed this compilation but a solution for patching kext for DW1520 (BCM943224HMS):

 

" Add this to config.plist:

 

<dict>

<key>Comment</key>

<string>DW1520 Whitelist Patch (MBP8,1)</string>

<key>Disabled</key>

<false/>

<key>Find</key>

<data>

TWFjLTJFNkZBQjk2NTY2RkU1OEM=

</data>

<key>Name</key>

<string>AirPortBrcm4360</string>

<key>Replace</key>

<data>

TWFjLTk0MjQ1QjM2NDBDOTFDODE=

</data>

</dict>"

 

It doesn't work eve having installed the FakePCIID and Brcm kext. Earlier compilation from November 2017 was worked, this from January 2018 don't work.

 

Also I'm trying dual boot macOS with Windows 10 Pro but after installing Windows it doesn't work...

 

I have SSD 120Gbb with partition table:

EFI on disk0s1

macOS on disk0s2

Windows on disk0s3

 

macOS was first installed with spilted disk, then installed Clover on EFI partition and finally Windows on third partition which corrupt Clover boot, it replaces to Windows boot EFI..

 

perhaps change to full identifier name? what do you see in the Clover boot.log?

change AirPortBrcm4360 to  com.apple.driver.AirPort.Brcm4360

[Horban]

 

 

perhaps change to full identifier name? what do you see in the Clover boot.log?

change AirPortBrcm4360 to com.apple.driver.AirPort.Brcm4360

I have changed wifi card to another DW1510 and card works without kext patch. Only I have added FakePCIID and Brcm kexts.

 

Only one question...

SM BIOS should be changed? I need use iMessage...

[Somez]

@somez and @rolitab

 

the 1600x900 config has an EDID injected as alternative. There are DSDT files included with this matching EDID.

you can turn off this custom EDID (in Clover option menu) or create an alternative config.plist file to test the native EDID from your BIOS/LCD. 

 

Also you try the various Aptio efi drivers  - try AptIoFix vs AptIoFix2 vs AptioFix3 to see how each behaves for you.

 

The EDID embedded in the config.1600x900.plist and the dsdt.edid.aml files - were designed to fix problems with the AUO vendor that come stock in many T420.

So if you have an LGD (or non-AUO) display then you may not need this fix. Sometime in the last 2 years, I replaced my LCD with a glossy $40 LGD option - which is looks and works 10x better than the poor AUO version. So I am going to run without the custom EDID injected to validate.

 

 

Hi tluck,

 

Before I jump into this, let me clarify a few things

 

you can turn off this custom EDID (in Clover option menu)

 

This should be somewhere at the Boot loader screen before I boot into macOS, right?

 

 

Also you try the various Aptio efi drivers  - try AptIoFix vs AptIoFix2 vs AptioFix3 to see how each behaves for you.

 

How do I do this? Start Clover installer and choose the customize option then tick/untick the necessary drivers?

Shall I try the APTIO fixes at the same time when I turn off the custom EDID injection on Clover options?

 

Thanks.

 

 

Update: went into the Clover options and unchecked the "inject custom EDID" option. I was able to boot into macOS with on problems so far.

 

Update #2: Well, no luck. I got a freeze after the display went into sleep due to inactivity. It's interesting that despite the freeze I don't see the BRSYNC errors in the log. And actually I've never had any of these freezes with Sierra on older Clover versions. 

Edited February 7, 2018 by Somez

[rolitab]

@somez and @rolitab

 

the 1600x900 config has an EDID injected as alternative. There are DSDT files included with this matching EDID.

you can turn off this custom EDID (in Clover option menu) or create an alternative config.plist file to test the native EDID from your BIOS/LCD. 

 

Also you try the various Aptio efi drivers  - try AptIoFix vs AptIoFix2 vs AptioFix3 to see how each behaves for you.

 

The EDID embedded in the config.1600x900.plist and the dsdt.edid.aml files - were designed to fix problems with the AUO vendor that come stock in many T420.

So if you have an LGD (or non-AUO) display then you may not need this fix. Sometime in the last 2 years, I replaced my LCD with a glossy $40 LGD option - which is looks and works 10x better than the poor AUO version. So I am going to run without the custom EDID injected to validate.

 

@tluck, thanks for your help. But I'm oficially giving up. It's too complacated for my understanding. I decided to do clean Yosemite install. But even here I got issues. It would be great to have some help on it... OK. Before updating to HS I had 100% working Yosemite 10.10.4. I made backup of ESP and HDD. But now I cannot boot in this backup installation for some reason. I boot from Yosemite-approved ESP backup which is on external USB drive. Then select HDD with Yosemite install in Clover menu. It starts to boot, I see apple logo and progress bar for a while, but then laptop restarts. Same thing happening when I try to boot from the same ESP to Yosemite Installation USB. It starts to boot, but then at some point laptop restarts. But I'm 100% that this ESP backup was working before, I didn't change anything there. It's really frustrating

[Somez]

@tluck, thanks for your help. But I'm oficially giving up. It's too complacated for my understanding. I decided to do clean Yosemite install. But even here I got issues. It would be great to have some help on it... OK. Before updating to HS I had 100% working Yosemite 10.10.4. I made backup of ESP and HDD. But now I cannot boot in this backup installation for some reason. I boot from Yosemite-approved ESP backup which is on external USB drive. Then select HDD with Yosemite install in Clover menu. It starts to boot, I see apple logo and progress bar for a while, but then laptop restarts. Same thing happening when I try to boot from the same ESP to Yosemite Installation USB. It starts to boot, but then at some point laptop restarts. But I'm 100% that this ESP backup was working before, I didn't change anything there. It's really frustrating

 

Have you tried booting the system in verbose mode to see the error messages? (press space on your installation and choose verbose mode)