Download Nomu S30 official stock firmware from the link here, and follow the provided flashing instructions to learn how to flash the stock rom.
If you notice that any of the links provided below is broken or doesn’t work, please post in comments section so we fix and update it ASAP.
Download Options
File Name: NOMU S30 1.0.9 Version.zip
Size: 2 GB
Version: 1.0.9
Firmware – Download
File Name: NOMU S30 Flash.(1.0.2 version).zip
Size: 1 GB
Version: 1.0.2
Firmware – Download
How to flash
After downloading the firmware from the above link, unzip or unpack the archive to find the firmware, flashtool, and flashing instructions.
Alternatively, you can follow the flashing instructions here.