W10 broke my working High sierra install

[NativeX]

TL;DR just in case this is common enough or there's another way around all this.
I need to either time machine backup using terminal in the recovery partition (or any other way of getting my data back?) or fix this issue; Installing W10 on a different drive managed to break the OSX boot (It wasn't plugged in whilst installing w10). Clover works but the boot fails. I've tried -x & -s

Previously I ran windows 7 and high sierra seperately with no* issues. Recently a friend gave me an old HDD so I did a fresh install of W10 and suddenly I can't do anything in my power to get OSX running any more. I disconnected all other drives while installing to make sure the install couldn't mess with anything, but that clearly wasn't kosher. I'm really stumped, the only idea i have is that W10 did something bios level but none of the relevant settings have been changed.
Making a new clover USB is going to be a pain, as i don't have home internet or another working mac at the moment

My boot flags when stable are dart=0 -xcpm kext-dev-mode=1
My install is based on this High sierra guide. Identical specs but with an imac wifi card

 

[P1LGRIM]

Moved to Multi Booting.

 

[NativeX]

Moved to Multi Booting.

My god I’m an idiot, I thought I’d copied the post over when I noticed it belongs there

 

[Going Bald]

TL;DR just in case this is common enough or there's another way around all this.
I need to either time machine backup using terminal in the recovery partition (or any other way of getting my data back?) or fix this issue; Installing W10 on a different drive managed to break the OSX boot (It wasn't plugged in whilst installing w10). Clover works but the boot fails. I've tried -x & -s

Previously I ran windows 7 and high sierra seperately with no* issues. Recently a friend gave me an old HDD so I did a fresh install of W10 and suddenly I can't do anything in my power to get OSX running any more. I disconnected all other drives while installing to make sure the install couldn't mess with anything, but that clearly wasn't kosher. I'm really stumped, the only idea i have is that W10 did something bios level but none of the relevant settings have been changed.
Making a new clover USB is going to be a pain, as i don't have home internet or another working mac at the moment

If all other drives were disconnected while installing Win10 there is no way it could have done anything to the Mac drive.
Double check your UEFI settings - in fact, I would suggest select exit tab, select default settings, and reset all of the Mac settings you changed to make HS run on the build. Then set the Mac drive as first in the BBS boot order so it boots from Clover.

 

[NativeX]

Done that All twice over... Do you see anything telltale in the verbose pictures? My only other step is a square one reinstall which I’m highly uninterested in doing

 

[Going Bald]

Done that All twice over... Do you see anything telltale in the verbose pictures? My only other step is a square one reinstall which I’m highly uninterested in doing

Try removing boot flag -xcpm
That seems to be where an exception error is occurring - can't quite make it out on that last page - too blurry, but looks like xcpm in the exception error just before it panics on cpucaller.

 

[NativeX]

Tried all combos of the existing flags to no avail. I did however manage to make a dodgey installer that got me far enough to time machine restore it, leading my only guess to this as being the EFI somehow getting affected by w10 but I'll never know.

I don't even know why i have -xcpm in there since it's not supposed to do anything on HS, right?

Anyways, I can't really call this fixed but the solution managed to work, thanks

 

[remington]

I would suggest installing macos to a different flash stick and boot from it. At least you will have working mac on it and able to access your computer or fix the EFI partition. Boot up will be slow but it works for emergency situations.

 

[NativeX]

Funny enough I'm trying to make a new drive now, both as a preventative backup and so I can update clover to get bluetooth working on my apple WIFI card, but I'm having trouble with booting the USB's EFI

Clover boots from the USB fine but there's no "Boot OSX from USB" option, just the usual SSD & Recovery partition and obviously the "Boot install macOS from USB"

 

[Going Bald]

Funny enough I'm trying to make a new drive now, both as a preventative backup and so I can update clover to get bluetooth working on my apple WIFI card, but I'm having trouble with booting the USB's EFI

Clover boots from the USB fine but there's no "Boot OSX from USB" option, just the usual SSD & Recovery partition and obviously the "Boot install macOS from USB"

Have you thought about trying it with an external drive connected USB - something like the WD Passport drives? Or just a bare SSD with a USB-SSD adapter - something like this for example:
https://www.amazon.com/dp/B00XLAZODE/?tag=tonymacx86com-20