FASTBOOT_SWTCH_PA
if (*((uint32_t *)(FASTBOOT_SWTCH_PA + FASTBOOT_STACK_OFFSET)) ==
*((uint32_t *)(FASTBOOT_SWTCH_PA + FASTBOOT_STACK_OFFSET)) = 0;
fb->fb_va = fb->fb_dest_pa = FASTBOOT_SWTCH_PA;