Yes. The driver package includes the fastboot interface. To enter fastboot on Jinka 721: Power off → Hold Volume Down + Power → Connect USB.

No. MacOS and Linux typically use generic USB drivers (MTP or ADB) without installation. This driver is Windows-only .

USB-to-Serial chip to communicate with your computer. Instead of searching for a "Jinka 721 driver," you should download the driver for the chip itself: CH340/CH341 Driver