@acer321
The ROM from ColonelZap is a so-called "Fastboot ROM", it is used with SP Flashtool (or other similar tools) which are used from a PC to flash a (powered down) smartphone and can be used to revive (soft-)bricked smartphones as it includes pretty much everything (besides device specific information stored in the NVRAM)
The ROM you downloaded from ACER is a so-called "Recovery ROM", it is used from the recovery or OTA Updater APP within your phone and therefore can only be used on a working smartphone. It contains much less data and is usually substantially smaller in size (usually not even 50% of the Fastboot ROM)
Try to get a Fastboot ROM or use the files from ColonelZap and update via recovery afterwards
The ROM from ColonelZap is a so-called "Fastboot ROM", it is used with SP Flashtool (or other similar tools) which are used from a PC to flash a (powered down) smartphone and can be used to revive (soft-)bricked smartphones as it includes pretty much everything (besides device specific information stored in the NVRAM)
The ROM you downloaded from ACER is a so-called "Recovery ROM", it is used from the recovery or OTA Updater APP within your phone and therefore can only be used on a working smartphone. It contains much less data and is usually substantially smaller in size (usually not even 50% of the Fastboot ROM)
Try to get a Fastboot ROM or use the files from ColonelZap and update via recovery afterwards