Linux 2.4.10 etherboot initrd init= problem

[cj]

Linux 2.4.10 etherbooting via mknbi-linux panics with:
....
Net4: Unix domain sockets 1.0/SMP for Linux NET4.0.
RAMDISK: Compressed image found at block 0
Freeing initrd memory 3084k freed
VFS:: Mounted root (ext2 filesystem).
Mounted devfs on /dev
Freeing unused kernel memory: 276k freed
Kernel panic: No init found.  Try passing init= option to kernel.

These kernel command lines work with 2.4.9 but not 2.4.10:
auto rw root=/dev/ram ramdisk_size=8192
auto rw root=/dev/ram init=/sbin/init ramdisk_size=8192
auto rw root=/dev/ram init=/bin/ash ramdisk_size=8192