Hello
Can I have 3 partitions on my Sd card (1 partition for HOS data, 1 partition for emummc and 1 partition for switchroot android ?)

If possible, what tool to use to setup?

Thanks

 

[CMDreamer]

Yes you can have all partitions you'd like, but you must take into consideration that some partition schemes, support only one primary partition.

One more thing, the fact that you can have many partitions on your card doesn't mean all OSes will make use of them in the way you intend to.

 

[binkinator]

Hekate/Nyx has a partitioning tool that will do all of this for you and even flash Android and/or L4T Linux for you. This includes making a hybrid mbr/gpt partition table.

This is covered in the #switchroot wiki here:
https://wiki.switchroot.org/