I got my hands on Redmi 1S through Flipkart.com. I purchased this for my Dad and wanted to give him a completely up to date phone. I could have updated it over the air (OTA) but my friend also had 1S and wanted to get the update. So, not to waste bandwidth and keep update file intact for future use, I opted for manual way. You can also do it as below.
Requirements:
1. Redmi 1S. Make sure your phone is charged at least 90%.
2. USB cable and PC / Laptop
3. Latest MIUI firmware update file. Get it from here.
At time of writing, latest available version was MIUI 45.0. Yours may vary.
Warnings:
1. The update files are usually huge so, make sure you use good internt connection and downloader. Incomplete zips or files; missing even 1 byte in size may kill your phone.
2. This update will reinstall all the stock apps which you may have removed. E.g. Google Street Map, MIUI assistant etc.
3. Data wipe is not needed if you are upgrading from old to new version. Data will not be affected with this method.
4. I am not responsible for any damages or data losses. It’s your choice to go manual.
Process:
1. First, connect the phone to your PC or laptop and transfer the zip file to phone card. Make sure you keep the file at very root of phone memory and not in any directory. From file manager, the location will look something like as shown,
2. Start ‘Updater’ app present in your Mi phone. It comes pre-installed and can be found under ‘Tools’ from the icon screen.
3. Select the ‘Option’ or ‘Menu’ (as some calls it) from Hardware key present on the left corner of the phone.
4. Click on ‘Select update package’ to get to file selection screen.
5. Select the update zip file by navigating to file and press ‘Update’.
6. You will get a warning to backup your data. This is an important step and you shall complete it if your phone is loaded with data.
6. After pressing ‘Start update’, phone will start updating itself and will announce that it is ready to reboot after successful installation. You may skip the reboot but I strongly recommend it to reboot it ASAP.
With new version, phone will take a little longer to reboot. Congratulations!