BootROM

The BootROM is located in on-chip ROM, and the storage address is 0x1840,0000, which cannot be dynamically updated. After power-on, each HART jumps to 0x1800,0000 (located in RAM) by default and starts to execute BootROM.

The main function of the BootROM is to select the boot source and execute it. According to different hardware jumpers on the chip, only UART and QSPI sources are supported currently.

Table 1. Boot Source Description
Source	Description
UART	Enter a simple command line. Load a limited size binary into the on-chip RAM and execute it. This mode is mainly used for firmware update.
QSPI	Automatically load the 32K Bootloader to 0x1800,0000 (located in RAM) from address 0 of NOR Flash and jump to it.

Note: The file loaded from NOR Flash cannot exceed 32KB.