LibreELEC require two partitions. You can follow my old post, just use the active grub2win *.cfg.
is it a solution for a single HD setup or can i use multiple hd´ s? The libreelec partions has to be the first partions?
Any partition on multiple HDs, usually grub can access any HD. Even the partitions can be on different HDs.
The next thing i realized is that the " aren´ t accepted by my grub2win Version.
I doubt that. But likely the grub2win app is managing the menu structure an you only need:
search --set=root --label LE_SYS
linux /KERNEL boot=LABEL=LE_SYS disk=LABEL=LE_DAT quiet ttyyou were right. But i am still not able to boot libreelec in a multiboot environment. Do you have any idea what´ s wrong?
I am hanging at the splash screen
i used the command chmod a+x on KERNEL and SYSTEM. Thanks in advance....
The "fail to initialize ptp_kvm" message is harmless and correct because you're not running under a KVM hypervisor. However if you got that far the good news is; the device has booted the LE kernel. If you remove "quiet" from boot params you'll see more output dumped onto the screen which might hint why the UI is not coming up. I also forget whether we still enable a local console to poke around in, but if we do (and we booted that far) it will be on CTRL+ALT+F3. I have a hunch the console output will stop when we load userspace, and this probably means we're failling to load it - although failure to find/load the SYSTEM file normally results on an obvious on-screen error message.
Local console is only enabled for installer mode of boot stick and does not work at all when using GBM. But for X11 using Generic-legacy image it is still possible, only kernel parameter has been changed with LE10.
Replace tty with systemd.debug_shell and you can use CTRL+ALT+F3 again.
Do i need to use the older nivida image with my system specs?
Yes, for nVidia cards you need the Generic-Legacy image. It's the only one that includes drivers for them. Using the normal Generic image would explain the lack of graphics 
