Downgrade android version from higher to lower? Mostly, android devices get updates through OTA to higher versions. I had upgraded to Kitkat(MIUI6) version, on my Redmi 1S using OTA. I have downloaded complete ROM of Jelly bean(MIUI5). But, I cannot install directly, it shows error and failed. That means an upgraded device cannot downgrade by direct installation. What should be done? (Unrooted device)
It depends on the manufacturer and the android version most likely. When there are new system updates, there are also often new bootloader versions available. Those are automatically updated to run on the newest software and provide support for the new android version. The installation of older software packages is often restricted by the newer bootloader. Some phones can be downgraded to older software versions of android by flashing a zip file via recovery or fastboot. But in the end it depends on which phone you have got and which android version you want to downgrade to.