Full dump is 1:1 copy of the original so thats the normal time. As for malware i never seen on infected. Read flash from such phone and upload somewhere. if you format the phone without reflashing you will kill it , unless that format you ask is in fact a RESET and that can be done easy from the recovery of the phone. You dont need a tool for that. NVRAM can read/write already by using READ PARTITION and after write fact firmware. Easy ! Learn how to use the tool before asking things
Br