The Stable update V6.6.2.0.KHHCNCF has been officially released for Redmi 1S TD 4G (codename is HM2014501). Before updating, please make sure you have downloaded the exact ROM matching your Xiaomi phone/tablet. In Fastboot mode, you can check model code by typing fastboot getvar product in cmd/shell.
The firmware files posted here are all official Xiaomi MIUI or HyperOS ROM, xiaomiROM.com do not own and never modified those firmwares，you will always download the file from Xiaomi server.
You may interest in those contents: Redmi 1S TD 4G ROM Topics Xiaomi Devices Index
Download Redmi 1s td 4g (HM2014501) China MIUI 6 V6.6.2.0.KHHCNCF Recovery ROM with Android 4.4. Firmware size is 480.8 MB.