When people say flash from hboot most often they are referring to flashing through fastboot, which is a mode within hboot/bootloader
Anyway, do this, get amonra's recovery, you'll find in dev section, rename it recovery.img and put it on root of SD card.
Now boot into os, download a terminal, open it up and type
su
---after this say yes grant super user permission then type
flash_image recovery /sdcard/recovery.img
-----if it works type
reboot recovery
If this doesn't work you may need to installed su, busubox, and flash_image binary
Sent from my Nexus 7 using xda premium