Steps to Configure INITRAMFS Boot - 2022.1 English

PetaLinux Tools Documentation: Reference Guide (UG1144)
Document ID
UG1144
Release Date
2022-04-26
Version
2022.1 English
  1. Set the RootFS type to INITRAMFS. For more information, see Configuring Root File System Type.
  2. Set INITRAMFS/INITRD Image name. The default image name is set to petalinux-intramfs-image to enable the switch_root. The build system generates two types of root file systems: ramdisk images and rootfs images. The ramdisk image is generated as specified in the INITRAMFS/INITRD Image name. It is packed into Fit image (image.ub) and Kernel image.
    Note: Setting petalinux-initramfs-image enables the switch_root and searches for the rootfs in ext2/3/4 of SD partitions. If switch_root is disabled load the final rootfs from RAM.
  3. Build the system image. For more information, see Build System Image.
  4. Use one of the following methods to boot the system image.
    1. Boot a PetaLinux Image on QEMU, see Booting PetaLinux Image on QEMU.
    2. Boot a PetaLinux Image on Hardware with SD Card, see Booting PetaLinux Image on Hardware with an SD Card.
    3. Boot a PetaLinux Image on Hardware with JTAG, see Booting PetaLinux Image on Hardware with JTAG.
Important: The default mode in the PetaLinux BSP is the INITRD mode.

In INITRAMFS mode, RootFS is included in the kernel image.

  • Image → Image (kernel) + ramdisk.cpio/rootfs.cpio (for Zynq® UltraScale+™ MPSoC and Versal® ACAP)
  • zImage → zImage (kernel) + ramdisk.cpio/rootfs.cpio (for Zynq-7000 devices)
  • linux.bin.ub → simpleImage.mb (kernel) + ramdisk.cpio/rootfs.cpio (for MicroBlaze™ processors)

As you select the RootFS components, its size increases proportionally.