Brick risk depends on which BootMii you had and what you did before deleting.
Deleting HBC alone is harmless — it's just a channel. But if you relied on it to launch Priiloader/BootMii, you may lose recovery access.
bootmii folder → BootMii loads? → Good (boot2).Post your exact steps on wii.guide or r/WiiHacks for expert review.