The Oppo A57 is a popular device from 2016-2017. Over time, users face these common scenarios that necessitate the Firehose file:
In all these cases, the standard SP Flash Tool (for MediaTek) or Odin (for Samsung) won't work. You need or MiFlash (which also uses Firehose) along with the dedicated Oppo A57 Firehose file. oppo a57 firehose file