Linux
Download links: https://sourceforge.net/projects/nippongsi/files/ Telegram channel: https://t.me/nippongsi
git clone --recurse-submodules https://github.com/kinguser981/GSI_TOOL.git
cd GSI_TOOL
bash setup.sh
Example: for making OxygenOS of oneplus 9 firmware, you can use this command
./url2GSI.sh https://oxygenos.oneplus.net/OnePlus9Oxygen_22.O.13_OTA_0130_all_2111112106_03a66541157c4af5.zip OxygenOS
check url2GSI.sh for more info