can't boot external drive with Intel-based Big Sur on a new M1

It makes sense that you can't boot an Intel OS on

an M1 machine. Even though they are both the

same macOS version, the code for each is totally

different and cannot be run.

The Rosetta 2 is only used within an M1 macOS to use

Intel apps.

Hello

I've been having the same problem:

Got a MBA M1 last week and have tried many ways to create an external boot drive that will work, testing both my new M1 and using another non-M1 Big Sur Mac(2018 Mac Mini) to create an external boot drive.

Here's what I've found after dozens of attempts:

• The M1 will not consistently create a bootable external boot drive on the M1. Probably less than 25% of attempts at creating such a drive are successful. I have tried multiple times at creating a drive using both Recovery mode Disk Utility to format/erase drive then install Big Sur, and/or using a USB stick install Big Sur method.
• If one tries to install Big Sur on a APFS encrypted drive, the OS will install but the drive is never visible to select as the Startup Disk.
• If successful in installing Big Sur on a APFS non-encrypted external drive, rebooting on that drive, and then turning on Filevault, the drive will not work as as bootable Startup Disk on next restart.
• I have tried many ways to create a bootable external drive using my non-M1 Big Sur Mac and I thought I was successful in getting the drive to be bootable on my M1 last week on one or two attempts. The last few days, however, I haven't been successful. There's now been so many attempts that my memory is fizzy and I might be wrong in thinking I was ever successful using a non-M1.

I was wondering about getting an external OS on the M1 Mac .

So even if you cloned the internal drive it would not work on the M1 Mac ?.

One good reason for me not getting one.I am using two Mac os s on my IMAC.

Turning on File Vault on an external drive that one wants bootable

seems questionable at best on any system.

Assuming you made the proper adjustments to the Security Settings in

booting into Recovery, have you also tried disabling SIP in terminal

(csrutil disable).

Also, have you updated to macOS 11.01? The original 11.0 shipped on

M1 Macs was creating all manner of issues in re-installing macOS and

11.0.1 was meant to resolve that.

Have you checked this? I don't have an M1, but read somewhere that you need to enable booting from an external while in Recovery > I believe it was in Disk utility, but also could have been part of the Menu bar choices?

babowa is correct. I have done this several times. You need to turn off the security settings in recovery from the top menu bar pull down menu that lists boot permissions. That being said even if that is done you may still find that you cannot make a boot drive. I have cloned the data volume to my external drive using CCC. Then from recovery installed Big Sur to that drive. That works but not with all drives. I have done this on 6 different SSD drives.. Some work and some only work 50% of the time (reinstall 2-3 times before it took) for some reason. I have only had 100% success using a WD M.2 drive in a TB3 enclosure. The process of installing Big Sur requires the Mac to reboot 2-3 times in the process so it appears the SSD design is critical. It should not be this way but it is for now until Apple makes a revision.

All this puts me off getting the M1

On the subject of drives not working with hardware. i have a CalDigit TS3 i had a problem with the T5 after a time it stoped working using the back Usb C 10gb ,I got in touch CalDigit i thought there was something wrong with dock. They got back to me saying it was something to do with the T5. Firmware.

I was asuming Caebon Copy cloner could do it.I don,t use the one builr in to Mac,s