Comment 3 for bug 1808056

So it seems after some testing that if one changes the boot.scr to this:

fdt addr ${fdt_addr_r}
fdt get value bootargs /chosen bootargs
setenv kernel_addr_r 0x01000000
setenv ramdisk_addr_r 0x03100000
fatload mmc 0:1 ${ramdisk_addr_r} vmlinuz
unzip ${ramdisk_addr_r} ${kernel_addr_r} ${filesize} || cp {ramdisk_addr_r} ${kernel_addr_r} ${filesize}
fatload mmc 0:1 ${ramdisk_addr_r} initrd.img
setenv initrdsize $filesize
booti ${kernel_addr_r} ${ramdisk_addr_r}:${initrdsize} ${fdt_addr_r}

then you can simply compress the vmlinuz in place with gzip and everything continues to work.