The previous answer is definitely the correct one, however, theoretically and with enough time, the A1000's boot ROM could be reworked to pilot your hard drive controller, interpret the Rigid Disk Block structure on the HD and eventually load a Kickstart either from a file with a filesystem (that would also require a small read-only OFS/FFS driver) or from a special partition. Then you would enable the Write Control Store and reset to the loaded Kickstart.
AFAIK, the original A1000 ROM code is a 8KB but the ROM chips themselves are two 8bit x 32K locations, so there is 64KB of space available.
I'm not aware of anyone that ever tried this way, however, not even back in the days when Commodore was alive.
Further expanding what I wrote, as it may be a bit more complicate that "just" talking to the chip and reading data from disk.
A potential hurdle could be bringing the HDD controller to life... investigation would be needed to see if the AutoConfig protocol can be activated on the controller in such an early environment (to be sure the controller card initializes itself so that the controller chip can be acted upon) and still end in a state where the next reset would reinitialize it.
Indeed, assuming A1000 hard drive cards even had AutoConfig!
It may be easier if the controller did not use AutoConfig, but then more investigation would be needed to understand where the controller maps itself in the address space.
In any case code in the eventual controller's ROM would probably not be useful as it would assume Exec running and if an autobooting one, that it is called via AmigaDOS's boot protocol.