The file boot.scr contains script that can be interpreted by U-Boot. Incorrect, boot.scr is not "run before u-boot.bin". If "there is no kernel parameter", then inspect the kernelx.img file what are the contents?īoot.scr is supposed to run before u-boot.bin. The default filename to load from the boot partition depends on the RPI version.Īccording to RPi documentation, the default kernel filename on the Pi 1, Pi Zero, and Compute Module is kernel.img, on the Pi 2, Pi 3, and Compute Module 3 it is kernel7.img, and on the Pi4 it is kernel7l.img parameter in the config.txt is an optional parameter that specifies an alternate (kernel) filename to load by the EEPROM boot program. How can it load u-boot if there is no kernel parameter in config.txt pointing to a binary u-boot?
Are there other ways of integrating u-boot in a RaspberryPi? Is there any documentation which describes these different integration schemes?.In this scheme how does u-boot know it must load " kernel7l.img"?.is uImage just another name for u-boot.bin?.How can it load u-boot if there is no kernel parameter in config.txt pointing to a binary u-boot? boot.scr is supposed to run before u-boot.bin. So here my questions for this boot process:
If test ! -e mmc 0:1 uboot.env then saveenv fi Ĭonfig.txt does not contain a kernel parameter. The readable part of boot.scr specifies that uImage will be loaded: value bootargs /chosen bootargs The boot directory of such an image contains: boot.scr, uboot.env, and uImage. I am here referring, for example, to Yocto recipes for the CM4 (meta-raspberrypi / u-boot). I would be super satisfied with this knowledge, but in practice I have (possibly) seen other ways of integrating u-boot. U-boot can then in turn load the actual kernel. It first reads " config.txt" which contains a kernel parameter. In the second stage the EEPROM boot loader finds and loads start.elf, whose task is to load the kernel.In this stage the BootROM simply loads the bootloader from the flash EEPROM. The first stage from the RPI cannot or should be modified.I am learning about u-boot and how this works in the Raspberry Pi system.
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