It appears to make a difference where the initramfs is stored.
Given an initramfs, rootfs.cpio.xz of size 39547768 and expanded size of 135067648.
bdinfo:
arch_number = 0x00000000
boot_params = 0x80000100
DRAM bank = 0x00000000
-> start = 0x80000000
-> size = 0x20000000
baudrate = 115200 bps
TLB addr = 0x9fff0000
relocaddr = 0x9ff48000
reloc off = 0x18748000
irq_sp = 0x9ef01d60
sp start = 0x9ef01d50
Early malloc usage: 530 / 2000
fdt_blob = 0x9ef01d78
If one uses low memory for the initramfs, the boot fails:
bootz 86800000 868a7000:25b7378 9eef8000
Kernel image @ 0x86800000 [ 0x000000 - 0x5f6168 ]
## Flattened Device Tree blob at 9eef8000
Booting using the fdt blob at 0x9eef8000
Using Device Tree in place at 9eef8000, end 9ef01ce4
Modify /soc/aips-bus@2100000/pxp@21cc000:status disabled
ft_system_setup for mx6
Starting kernel ...
If one instead uses high memory, the boot succeeds:
bootz 86800000 9B9F0000:25b7378 9eef8000
Kernel image @ 0x86800000 [ 0x000000 - 0x5f6168 ]
## Flattened Device Tree blob at 9eef8000
Booting using the fdt blob at 0x9eef8000
Using Device Tree in place at 9eef8000, end 9ef01ce4
Modify /soc/aips-bus@2100000/pxp@21cc000:status disabled
ft_system_setup for mx6
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0
However, if one tries to use the gzip equivalent file, which is about 53MB instead of 38MB, the initramfs is corrupted:
Kernel image @ 0x86800000 [ 0x000000 - 0x5f6168 ]
## Flattened Device Tree blob at 9eef8000
Booting using the fdt blob at 0x9eef8000
Using Device Tree in place at 9eef8000, end 9ef01ce4
Modify /soc/aips-bus@2100000/pxp@21cc000:status disabled
ft_system_setup for mx6
Starting kernel ...
...
[ 9.372882] rootfs image is not initramfs (write error); looks like an initrd
[ 9.373011] /initrd.image: incomplete write (-28 != 55073391)
[ 9.536524] Freeing initrd memory: 53784K
