: If you bought the phone secondhand, ask the previous owner to sign in to iCloud.com/find and select Remove from Account for the device.
The exploit requires the device to be in DFU (Device Firmware Update) mode.
Holding... Bypassing the iCloud Activation Lock on an running iOS 10.3.4 can be achieved on a Windows PC using specialized tools that exploit older hardware vulnerabilities. Popular Bypass Tools for Windows
: Most free bypass methods for iOS 10.3.4 do not support calling or SMS. The device is essentially used as an "iPod" via Wi-Fi. Untethered vs. Tethered
True "Signal" bypasses (allowing phone calls) on iPhone 5 are rarely free. Free tools usually result in a "No Signal" device (usable as an iPod/iPad only).
: Tools like Sliver (originally for Mac but often adapted) or dedicated Windows-free tools like those seen on YouTube are common.
By following this guide, you have successfully transformed your legacy iPhone 5 running iOS 10.3.4 from a brick into a functional device using nothing but a Windows PC. Enjoy your second-life iPhone!