Switch from CSM to UEFI

[Per E. Johannessen]

I have a system with AOS 5.0.4 and Win10 installed on separate disks, (using AirBoot, CSM).
Does anyone have a "step by step" for how to switch from CSM to UEFI ?

[ivan]

I have to ask, why change a very good working system to pander to Intel and Microsoft?  I have to say I am of the old school of 'if it ism't broken then don't fix it'.

[Per E. Johannessen]

Agree with the "if isn't broken etc." but I have to replace the graphics card and the new one I got needs UEFI.

[Dave Yeo]

Agree with the "if isn't broken etc." but I have to replace the graphics card and the new one I got needs UEFI.

Hopefully it isn't some card that uses a lot of memory or put the frame buffer above 4GB.
First you are going to need AOS 5.1 or newer. Simplest is to do a EUFI install, change to UEFI boot in the BIOS. You will need a UEFI partition, which Windows may have already created, otherwise about 256 MB FAT32 partition that will, if needed, be created during the install assuming you have the empty space. Can't remember if it needs to be a primary.
Then install AOS 5.1
Updating, IIRC, is not supported from a BIOS boot to UEFI though it is possible with work.

[Neil Waldhauer]

Check the Arca Noae Wiki for that.

https://www.arcanoae.com/wiki/

[Per E. Johannessen]

I have Win10 but since it's been run with CSM it has not created any ESP partition. AFAIK updating Win10 to Win11 requires UEFI so I assume that the updating process will create the ESP partition, (the Win10-disk has enough free space).
Before updating to Win11 I think I will disconnect the AOS-disk and only have the win-disk and another empty disk in the system.
If the win updating goes well I'll install latest AOS to the empty disk.

Finally I plan to re-connect the older AOS disk and wonder if there is something I have to do manually or will it be seen automatically and added to whatever boot manager AOS 5.1 sets up?

The graphics card is a Radeon RX 7800 XT and I have no idea about the size of the frame buffer or where it is put.
 
I have checked https://www.arcanoae.com/wiki/ and the info is good for a new installation however I initially had a hope of "converting" an existing AOS installation to UEFI. Couldn't find any info for that scenario so I'll go for a new 5.1 installation.

[ivan]

Another thing to consider is changing the mother board to one that takes an AMD Ryzen processor with built in graphics.  I converted all my computers to AMD processors, my main unit runs a 30 inch 2560 x 1600 screen without problems.  Also, as Dave says be very careful with UEFI graphics cards - they are not all created equal and may not work with OS/2 - ArcaOS..

Strange as it may seem I was reading up about the problems of converting win 10 to win 11 because some friends of mine were thinking of doing so and it appears that there isn't any real advantage in doing that.

[Dave Yeo]

Finally I plan to re-connect the older AOS disk and wonder if there is something I have to do manually or will it be seen automatically and added to whatever boot manager AOS 5.1 sets up?

Without using CSM, no. I currently have CSM enabled and am using UEFI boot. My boot manager, rEFInd, can load airboot allowing me to do a BIOS boot. If I disable the CSM, only pure UEFI booting is possible.
You likely would have to go into the BIOS to toggle CSM on to boot your older install.

[Roderick Klein]

I have Win10 but since it's been run with CSM it has not created any ESP partition. AFAIK updating Win10 to Win11 requires UEFI so I assume that the updating process will create the ESP partition, (the Win10-disk has enough free space).
Before updating to Win11 I think I will disconnect the AOS-disk and only have the win-disk and another empty disk in the system.
If the win updating goes well I'll install latest AOS to the empty disk.

Finally I plan to re-connect the older AOS disk and wonder if there is something I have to do manually or will it be seen automatically and added to whatever boot manager AOS 5.1 sets up?

The graphics card is a Radeon RX 7800 XT and I have no idea about the size of the frame buffer or where it is put.
 
I have checked https://www.arcanoae.com/wiki/ and the info is good for a new installation however I initially had a hope of "converting" an existing AOS installation to UEFI. Couldn't find any info for that scenario so I'll go for a new 5.1 installation.

The reason its not a common support scenario is indeed because if it works it works. Its also not that easy to automate conversion to a UEFI system.  The primary thing is that you need a new partition and converting the HDD to gpt disc layout is more complex yet again (if you want this). Could Arca Noae have developed this code ? Perhaps. But its pretty complex code.

Roderick

[Neil Waldhauer]

Perhaps it isn't that hard. I think you could do this experiment.

Install ArcaOS 5.1 on the system you have now.
Install the new graphics card and switch to UEFI
Install ArcaOS 5.1 on a different volume.
Compare the Config.sys. I think only a graphics has changed.
Make that change and copy the files it refers to to the first ArcaOS installation config.sys
See if the first installation now boots under UEFI

Make sure you have space to make the new boot volumes and also the EFI volume.

[Roderick Klein]

Perhaps it isn't that hard. I think you could do this experiment.

Install ArcaOS 5.1 on the system you have now.
Install the new graphics card and switch to UEFI
Install ArcaOS 5.1 on a different volume.
Compare the Config.sys. I think only a graphics has changed.
Make that change and copy the files it refers to to the first ArcaOS installation config.sys
See if the first installation now boots under UEFI

Make sure you have space to make the new boot volumes and also the EFI volume.

you also need an ESP partition.... Effectively UEFI boot no longer uses an MBR.
Airboot stops working to any dualboot options will have to be setup again.

Roderick

[Martin Iturbide]

Hello Per.

I haven't used it myself, but Rich Walsh wrote a command line utility called CSM2UEFI.

You can check it out here: https://www.os2world.com/forum/index.php/topic,3423.msg41061.htmlv

Reegards

[Rich Walsh]

converting the HDD to gpt disc layout is more complex yet again (if you want this). Could Arca Noae have developed this code ? Perhaps. But its pretty complex code.

Years ago I wrote an MBR-to-GPT converter that worked with any LVM-compliant disk and didn't require moving or copying the disk's contents. In fact, after conversion, you could use the disk as MBR _or_ GPT until you changed the partition layout. I offered it to AN but the person I dealt with couldn't imagine any use for it and declined the offer.

[Per E. Johannessen]

Interesting. Could the MBR-to-GPT converter be used on a win10-disk/NTFS  as well?
(I have so far not assigned any drive letter/LVM info for that disk.)

[Rich Walsh]

Could the MBR-to-GPT converter be used on a win10-disk/NTFS  as well?

This has nothing to do with the filesystem and little to do with the OS.

GPT uses the first 34 sectors  of the disk as well as the last 33 sectors for its headers and partition tables. These sectors are always unused on an LVM-compliant disk, allowing them to be used for GPT without overwriting anything else on the disk except for the MBR itself. An MBR disk that was created by Win probably has the initial sectors free (because it aligns partitions on a 4MB boundary), but the last sectors are likely included in an existing partition which would have to be resized.

Note 1: I overstated the converter's capabilities. Once converted to GPT, the disk cannot be used as an MBR disk without restoring the original MBR sector (which the converter saves so the change can be rolled back).

Note 2: My MBR-to-GPT converter is not freeware. If someone wishes to pay $2,500 USD, I will provide an unlimited-use license allowing them to resell individual copies, post it to hobbes as freeware, include in AOS, or whatever. I have no plans to issue individual-use licenses.