This is what worked for me,
1) Turn off acceleration in the Intel Rapid Storage Tech. It will take a while.
2) Click reset to available (it will show up once you disable acceleration) which should remove the fake raid thing and free your SSD.
3) Use some disk utility such EaseUs, to turn your HP Recovery and HP_Tools partitions to logical. Now, you should have atmost 3 primary partitions. If not, then make sure that you don't have more than 3 by changing to logical/removing unnecessary partitions that you may have created. Create some unallocated space from one/more of the partitions. ~10GB is good. DO NOT CHANGE BOOT PARTITION TO LOGICAL.
4) Restart and enter BIOS, turn off the Intel Rapid Start Tech.
5) Install using live USB by selecting "Something Else" in the unallocated space.
6) Now, you may turn on Intel Rapid Storage and Intel Rapid Start. The exact same config in the Intel Rapid Storage cannot be restored so what you could do is make 18.6GB cache volume and the rest data volume. From that data volume, you could turn 4GB into hibernation partition using command prompt and use the rest for storing any files that you access frequently.
* Apparently, there is no way to put back the same config of 4GB data(hibernation) volume and 26GB cache volume.
* All this may seem to be out of the blue and look like as if I am talking about random stuff but if you have googled enough, you'd know what I am talking about.