@ ucode and error-id10t:
Meanwhile I was able to recreate the RAID0 array by using the "Intel(R) Rapid Storage" tab of the UEFI BIOS and to get Win8 x64 properly installed in EFI mode onto the RAID0 array. The "System reserved" 350 MB sized partition, which is part of the array, is shown as active, that means it contains the boot sector and the GPT.
Nevertheless there are 2 problems to be solved:
- It is impossible for me to disable CSM. As soon as I do it, I get the message "The current BIOS settings do not fully support the boot device. Click OK to enter the BIOS Setup."
- Although I had unplugged my 2 TB HDD (with no OS, just Data) until the Win8 installation had been completed, the system has set the first partition of the HDD as "active" as soon as I reconnected the HDD.
Now I would like to know,
a) which BIOS settings are needed to fully support my RAID array as boot device and
b) why has the first partition of my DATA HDD has been set as bootable.
Any advice is much appreciated.
I am sorry about this rather OT discussion. If needed, it can be continued by PM.