MP 1,1-5,1 install UEFI windows in cMP5,1

[supersaian]

hi, i have joined this forum formany years, i seldom post anything because i am not a tech. but this forum helped me giving me information to let me ipgrade my cMP 5,1 from 2012 to now which is nearly a decade. i would like to thank all the dearest users here.

As time goes by, my 5,1 was upgraded with RX580 and installed Monterey with injection of opencore, however, my usual bootcamp (running windows 11) now is unable to be boot using the mac start up preference panel, this bootcamp is located in another physical 3.5” SSD, In order to use windows, i created a new partition (WIN10 named) and 200M Fat32 partition (for opencore) trying to install uefi windows 10 in the pci ssd (installed Catalina & Monterey in APFS) i follow the steps at opencore, because i have no boot picker with RX580, so i blessed the opencore drive (200M Fat32 partition) in order to make it boot from opencore, everthing looks good untill the windows installation said “windows could not prepare your computer for next installation phase”

i am trying to google for whole week but still not found any other people’s similar experience to follow. I updated the mbr bootcamp windows for so many many times from windows xp to windows 11 now without problem, but just unable to install an uefi windows 10 now, what comes up in my mind now is my CMP display card is not EFI capable now.

i would like to ask for help to light me up a path to success, thanks in advance for all of you forum users.

 

[Macschrauber]

Before fiddling with uefi Windows make a backup of your boot rom.

In case you got certificates you can get them away by flashing the backup.

If there are still certs in better get someone who can remove them.

My dumper makes a backup and check certs

Healthy NVRAM normal behaviour on 4,1->5,1 machines

Macschrauber's Rom Dump I needed to encrypt the disk image as DropBox has flagged it for containing Flashrom. The password is rom. What's new in the latest versions: Update from 20-2-2024 -> checking Fsys for missing items or wrong order sometimes they get into the wrong order or items...

forums.macrumors.com

 

[supersaian]

Before fiddling with uefi Windows make a backup of your boot rom.

In case you got certificates you can get them away by flashing the backup.

If there are still certs in better get someone who can remove them.

My dumper makes a backup and check certs

Link is in description.

thanks your reminds, i never thought about this.

 

[supersaian]

For the information who interested:
i finally figured out, windows 10 is installing now, i can not wait to share my experience here with all fellow users.

After Tried all possible methods without open up my cMP case, i opened it this morning and pulled out my Nvme SSD.

Then boot system via SATA opencore partition, select windows 10 usb to further boot, start windows installation, then all good, good good.

That’s all my share.

 

[supersaian]

Finally, i tried to install uefi windows to the Samsung EVO 850, using an ATI 5770 apple original display card, the installation process is fast because it is an SSD.

i changed in the windows device manager to use the most simple display driver, then change back to rx580 metal display. The machine boots into windows nicely. Then widows detected the display card and it changed itself back to using a RX580 display card driver provided by windows. All the things seems good. so i put my M.2 and other SATA disks back in. ALSO plug back the newer monitor with a HDMI cable. Then switch the cMP on. However, it will not boot into windows anymore, stop right at the windows logo.

After a few times trying to boot into windows, i changed the monitor back to a dvi-d connector, entered to windows safe mode, changed the display card driver back to the most simple one. Finally, windows is booted up again. (i tried this procedure before change to a DVI-D monitor without success) and then i installed the AMD driver download from AMD site, after i rebooted successfully, i changed back to the HDMI monitor. Finally, the fight ends, cMP booted into windows. At last, i upgraded to windows 11 with the famous media creation tools from Github.

The fight is too long now, i remember this is the 3rd week now, so i did not try to further find out the problem was related to the M.2 or the HDMI display.

But my experience this time tell me do not use a HDMI monitor to install windows in a cMP 5,1. i feel this is the main reason of all the previous unsuccessful installation of windows in these few weeks. The is the end now.