Cisco ASA 5505 upgrade
So i would expect, that the ASA would have bootet the old image, if there were boot entires: boot system disk0:/asa914-k8.bin. boot system disk0:/asa923-k8.bin . but not a situation where the asa will hang within the boot process. Even if you sould have deleted the old image, i would expect the ASA to boot the remaining image.