I got a few Racerstar ESC's (a set of 30A v2 and a set of 20A v2), which I so far have always run on Oneshot125. In the product description of the ESCs it says "[...] Support Oneshot42 Multishot [...]" so it should support it but it's not apparent to me how to go about getting there. I've never gone beyond Oneshot125 so it's new territory for me.

I've seen various tutorials pointing to RS2K's post on RCGroups which points to a download page listing multishot firmwares for various popular ESCs. The Racerstar ESCs aren't in that list though and it's my guess that it's not smart to take risk flashing some random firmware to an ESC. 

My questions:

• Has anyone flashed Oneshot42/Multishot to their Racerstar ESCs? If so, which firmware did you use?
  
• a more general question: can 1 single firmware support Oneshot125/Oneshot42/Multishot or are these always dedicated firmwares?
  

Thanks! Hoping to prevent a fireball

I believe that blheli_s recognizes communication protocol automatically. I have just set multishot on my FC and it worked with EMAX blheli_s ESCs.

Standard pwm/oneshot/multishot are detected automatically, you only need to set it in FC. Same firmware supports them all.

You're very right, thanks! I guess I was thrown off by the tutorials pertaining to pre-BLHeli_s ESCs.