"Factory firmware" refers to the software that comes pre-installed on a device when it is manufactured. It controls how the device operates and cannot be easily changed or modified by the user. Full definition
I haven't had any problems with mine whatsoever, except for it not keeping the sleep timer setting on the original factory firmware. (blog.the-ebook-reader.com)
This page contains binary image files that allow you to restore your Nexus or Pixel device's original factory firmware. (developers.google.com)
I need factory firmware for Samsung shv - e160s 32gb phone include pit bootloader pda modem csc, if any one have please share. (sammobile.com)