Hi.
Surely those instructions are in the wrong order?

You seem to be creating the newMBR and newPBR (merging original MBR with boot0ss, to retain partition table), after writing to the disk. The merged MBR and PBR don't ever get written to the disk.
Or am I being stupid?

$ sudo dd if=newPBR of="/dev/sda1" bs=512 count=1
$ sudo dd if=newMBR of="/dev/sda" bs=512 count=1 conv=nocreat,notrunc
$ sudo dd if=origPBR of=newPBR skip=3 seek=3 bs=1 count=87 conv=notrunc
$ sudo dd if=boot0af of=newMBR bs=440 count=1 conv=notrunc