If your Vivo Y15 is working slow due to its firmware, you will need to follow the simple steps below. First of all download the firmware of your phone, then put it in one specific folder in C: Program Files. Take a backup of your data which is on your phone. After that download and install the latest USB driver of your mobile manually.
The Vivo Y15 is powered by a Quad-core 1.3 GHz Cortex-A7 CPU processor with 512 MB RAM.
The device also has 4 GB internal storage + microSD (up to 128 GB) and a 4.5-inch Capacitive touchscreen (480 x 854 pixels, 218 PPI) display. It has a 5MP rear camera and supports Wifi, GPS, and 3G.
It packs in a Li-Ion 1900 mAh battery at 9mm device thickness and weight 130g, running on Android OS, v4.2.2 (Jelly Bean).
You can install several apps at a time