Here's a good video about CellMapper:
Yes, mapping bands should work on Lumia 550 like on all other Windows 10 Mobile phones. And screen can be off while mapping.
wow , on lumia 550 block band and maps correctly 2g 3g 4g band?also maps with screen off?
Yes, mapping bands should work on Lumia 550 like on all other Windows 10 Mobile phones. And screen can be off while mapping.