When booting an embedded Linux system built with PetaLinux, the following message is displayed when handing off between UBOOT and the Linux kernel:
PetaLinux builds FIT images (image.ub) which contain the Linux kernel, device tree, and root filesystem.
As the FIT image size increases UBOOT might not be able to decompress the FIT image in the amount of memory allocated for this operation.
The size of the GUNZIP area can be increased by setting the CONFIG_SYS_BOOTM_LEN variable in the UBOOT configuration header (<PETALINUX_PROJ_DIR>/subsystems/linux/configs/u-boot/platform-top.h).
The maximum allowable size for this variable is defined in the common header for the CPU architecture of your target system (Zynq - https://github.com/Xilinx/u-boot-xlnx/blob/master/include/configs/zynq-common.h)