The Flash Striper Utility Section in the QEMU User Guide (UG1169) requires a flash_stripe.c file to stripe a single QSPI data image and format it into two images.
This file is currently not present in the QEMU utilities being shipped with PetaLinux.
Please download flash_stripe.c attached to this Answer Record and follow the instructions below to build it.
Steps to compile:
gcc flash_stripe.c -o flash_stripe -DFLASH_STRIPE_BE -DFLASH_STRIPE_BW
Note: this is useful if you need to split the flash file into lower and upper flash for dual parallel emulation.