Under construction…
X-Boot is the first-stage boot loader. It is loaded into internal SRAM and run by internal ROM code of SP7350. Note that before X-Boot initializes and trains DRAM controller, DRAM is not available.
X-Boot initializes and trains the SDRAM controller, preparing the DRAM for use. Subsequently, it loads the TF-A (Trusted Firmware-A) and OP-TEE (Open Portable Trusted Execution Environment) images from the fip (firmware image package) partition within ISPBOOOT.BIN, storing them in DRAM. Additionally, the U-Boot image is extracted from offset 0x30000 of ISPBOOOT.BIN and stored in DRAM. Upon successful checksum verification for all images, the system proceeds to execute TF-A, followed by OP-TEE, and finally U-Boot.
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x-boot is loaded and run at SRAM before DRAM is available.
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