Many users want to to go back to iOS 10 or 12 for performance or jailbreak reasons. Unfortunately:
No. The iPhone 6 uses iPhone7,2 firmware; flashing iPhone8,1 will hard brick it. download ios firmware for iphone 6s
Click the link above (or from IPSW.me) to download the .ipsw file. Save it to an easily accessible location (e.g., Desktop). Many users want to to go back to
Do use random third-party forums. Corrupted or modified IPSW files can permanently brick your device. Always use trusted sources. download ios firmware for iphone 6s