Windows 10 1.726 Themen, 20.447 Beiträge

Bootreihenfolge, UEFI fehlt

Andy30 / 84 Antworten / Flachansicht Nickles

Um ein Backup zurückzuspielen, habe ich ein sog. WinPE-Notfallmedium auf CD erstellt.

Um von CD zu booten, habe ich im (UEFI-)BIOS in der vorherigen Bootreihenfolge

1. WinBootManager
2. UEFI
3. Samsung-SSD (stand 2x drin, weiß nicht mehr welche zuerst, es sind 2 SSDs eingebaut, C: und D:)
4. CD-Laufwerk

das CD-Laufwerk an die erste Stelle verschoben.

Booten von der CD versucht (Backup-Software startet kurz an, doch während des Ladens erfolgt wieder Neustart des Systems).

Nun wieder im BIOS die Bootreihenfolge versucht zurückzustellen, doch jetzt fehlen die Einträge "UEFI" und die zweite SSD. Vorher kam kurz die Meldung "NTLDR fehlt".

Wie bekomme ich die jetzt fehlenden Einträge im BIOS wieder zurück?

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winnigorny1 Andy30

„Habe mir den Link mal mit Google ins Deutsche übersetzen lassen. Es geht dort zwar vorrangig um die Installation von ...“

Optionen
aber die Problembeschreibungen decken sich vielfach mit meinen.

und wie ist es hiermit:

"I figured out why in the pre-Windows installation environment and with CSM disabled that I could not see any of my storage devices in the “Boot Option Priorities” or “Boot Override” lists.

Back in the old days of Legacy BIOS booting, all storage devices showed up in boot lists where you could arrange their priorities and select one to boot from. Now with UEFI BIOS, only UEFI-bootable devices show up in those lists, unless you have enabled CSM. Disabling CSM is for UEFI-only booting, and the only devices that show up in boot lists are devices that contain \EFI\Boot\bootx64.efi in the root directory. That is the UEFI "boot loader". If I had installed Windows on the Samsung 960 Pro then \EFI\Boot\bootx64.efi would appear in the EFI (“System”) partition of the drive, and the boot list would show "windows Boot Manager" or “UEFI: Samsung 960 Pro” or something like that.

The DVD drives did not show up in the boot lists with CSM disabled because they did not contain any disks. If I insert the Acronis/WinPE rescue disk before booting into BIOS, then the DVD drive shows up as “UEFI: Pioneer BD-RW BDR-209M” because that disk contains the directory \EFI\Boot\bootx64.efi. Same for a Windows 10 Recovery thumb drive I made for a different computer, for booting into the WinRE environment. It shows up in the boot device list as “UEFI: SanDisk Ultra USB 3.0 Flash Drive” because it too contains \EFI\Boot\bootx64.efi as I’ve verified.

So with CSM disabled, the ASUS UEFI Bios will examine all HD, SSD, USB ports, and DVD drives, looking for UEFI bootable devices that contain \EFI\Boot\bootx64.efi. In contrast, if CSM is enabled then all devices show up whether or not they contain \EFI\Boot\bootx64.efi. With CSM enabled you will then see two versions for example “P3: Pioneer BD-RW BDR-209M” and “UEFI: Pioneer BD-RW BDR-209M”, giving you a choice of booting to the device with a Legacy BIOS boot or a UEFI boot. The Legacy boot will not use the \EFI\Boot\bootx64.efi boot application, but will instead use the application named bootmgr.

So I can in fact leave CSM disabled and install Windows, and if I ever need to boot from an Acronis rescue disk or a Windows Recovery thumb drive, I can either press "F2" or “DEL” and boot into bios and select the device from the “Boot Override” list, or spam the “F8” key during boot after the ROG logo appears, to bring up the “Please Select Boot Device” menu which will list all devices containing \EFI\Boot\bootx64.efi. If I ever need to boot from a non-UEFI compliant device that does not contain \EFI\Boot\bootx64.efi then I'd have to enable CSM first if possible (and probably have to disable Secure Boot). That is my understanding.

CSM IS ENABLED BY DEFAULT, so people who want a pure UEFI boot system will want to disable CSM before installing the OS.

Here are some good resources I found:
A Youtube video: “How to Fix Issue Booting to DVD/CD with New UEFI BIOS Boot Order” https://www.youtube.com/watch?v=y8Ml1IbVp-8 where he had an Acronis rescue disk that did not contain \EFI\Boot\bootx64.efi, and so he had to go into BIOS and enable CSM & disable Secure Boot in order to boot from it.
Also an old but excellent and still relevant discussion by Sushovon Sinha “UEFI Secure Boot in Windows 8.1” https://answers.microsoft.com/en-us/...a-57fa783f0759 which is full of good technical information."

Habe ich in diesem Thread gefunden:

https://rog.asus.com/forum/showthread.php?96196-I-need-advice-on-CSM-and-Secure-Boot-settings

Hat wohl auch etwas mit meinem Problem, das ich mal mit Acronis hatte, zu tun......

Grüße aus Hamburg, Winni - https://www.das-bumerang-projekt.de
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