CSMwrap works for me, but works only on MBR disk, not GPT

[The-Solutor]

Hi I tested CSMwrap on my HP Elitedesk 705 Mini (a Ryzen 2400G machine)

In short that machine still has its own CSM support, but for some reasons, if I enable it and I disable Hyper-V (via a BCD parameter) the VGA driver isn't loaded correctly.

I tried everithing w/o any success.

I have either to enable Hyper-V or disable the native CSM to have the VGA working correctly.

Then I decided to try CSMwrap and IT WORKS.

Native CSM is disabled and I can boot with or w/o Hyper-V at will.

But I noticed that I can boot only from the SATA disk (which is MBR) but not from the NVME (which is obviously GUID).

Not a huge problem for me given the OSes installed in the NVME disk are still bootable via an entry in the SATA BCD, but still I need two disks to get all the thing working.

So I ask, if this is supposedly the normal working way of CSMwrap, or there is a bug that prevents booting from a GUID disk if a MBR one is attached?

To be clear the NVME disk is shown pressing ESC, but if I select to boot from it CSMwrap tells me that no bootable device is found.

Aside that the USB management isn't rock solid, sometimes the keyboard is dead during boot time, sometimes it works correctly.

P.S. for the record on that machine I tested Win 7 x64 (works perfectly) Win XP and Vista (either 32 or 64 bits) they attempt to boot but then throw the infamous non ACPI compliant error (even with a patched acpi.sys driver)

[Gelip]

CSMWrap is legacy mode. Windows not support GPT disk on legacy mode.

[The-Solutor]

Windows?

You seem pretty confused.

Obviously windows supports GPT disks in legacy mode, partially since server 2003/xp64.

And like I said I can boot systems installed on the GPT disks starting with CSMwrap, but I need to use the BCD on MBR drive.

What I asked to @FlyGoat was if that is the intended behavior or if that's a bug,

That's all

[Gelip]

@The-Solutor As you write yourself you need an MBR disk to boot so it is not booting from GPT.

[The-Solutor]

@Gelip

Please stop with your usual nonsense, if you haven't anything useful to say.

First you say that windows in legacy mode doesn't support GPT disks (which is obviously wrong), now you talk about the bootloader....

Whatever... I solved my problem using Clover, so I boot from the GPT disk or from the MBR disk, or I can chainload CSMwrap taking advantage of its features, using a simple menu

As a bonus this way the USB keyboard is always detected by CSMwrap.

Still would be nice to have CSMwrap to do the job by itself. So the question for @FlyGoat is still valid.

[FlyGoat]

So you have BCD on a MBR SATA disk with system on another NVME disk, and you intended to put CSMwrap on the NVME Disk?

I'm really confused...

[The-Solutor]

I have two disks one is GPT one is MBR.

Both of them are bootable on their own

BCD is present in both of the disks

Each BCD is configured with many entries to many OSes placed on both disks. and (on the untouched system) they are all working no matter if I boot from MBR or UEFI.

BUT the stock CSM lead to the problem I mentioned with Hyper-V, so I decided to use CSMwrap that FIXES the Hyper-V problem AND allow me to use Win7 booting from UEFI with the stock CSM disabled.

Now my "problem" (better to call it observation) is that CSMwrap sees only the BCD on the MBR disk.

CLOVER sees both of them and with a custom entry in the CLOVER menu I can launch CSMwrapper as well.

I wish that CSMwrapper did the same w/o the intervention of a further layer, but for now I'm more than satisfied of what I got.

I hope it's finally clear what's my question.

Immagine a random user who has only a single NVME disk and wants to add a legacy OS to its multi boot list.

W/O the support for the GPT partition he can't do anything other than converting the disk to MBR with the risk to get an unbootable system before even trying if CSMwrap works (keep in mind that normally a NVME disk needs to be GPT formatted to be taken in account by the UEFI firmware, with few exceptions like the infamous Samsung 950 Pro).

Not my personal scenario but definitely not a great perspective.

[dietmarpapagei1]

@The-Solutor You can boot from an nvme disk, just with mbr and ntldr Dietmar

[The-Solutor]

@dietmarpapagei1

1. It depends on the firmware. On early UEFI MB booting a MBR formatted NVME disk was out of question. That made CLOVER and DUET/rEFIND so common. I personally used for years Clover to boot a NVME disk on a Ivy bridge system. Modding the FW was also very common, but out of question on that MB, given the uncommon INTEL FW installed on it.

Obviously in the above case Clover was used in the opposite way: Boot from a MBR pendrive or HDD, then clover loaded the UEFI system from the NVME disk.

Now I'm doing exactly the opposite: I boot from UEFI, then Clover loads the MBR boot manager, or the UEFI one or chainloads CSMwrap, which in turn loads the MBR bootmanager.

2. Forget ntldr, It has nothing to do here, and in case it was, ntldr was installed in it's own VHD (I never install my OSes directly on partitions, each OS in installed in its own VHD/VHDX, each Linux I use is installed in its own loopback IMG or VHD file). I stopped messing with creating/resizing partitions 15 years ago.

3. Even in normal XP installations I never use the "standard" way. I use /NT60 partitions, then I rename ntldr as bootmgr.

Way less troubles resizing/moving/restoring/converting partitions that sometimes become so corrupt that can't be made bootable in any other way. With NT60 partitions it never happens