dd if=/dev/sda1 of=/dev/sdb1
Well, then you only copied the first partition of the hard drive, not the MBR, because the MBR is not part of any partition. You'll have to do something like
dd if=sda of=sdb
i.e. copying the entire drive, to clone the MBR. If you know exactly how long the MBR is, you can use the "bs" and "count" arguments of dd to selectively clone the MBR only.
However, if you still have the source drive, I suggest using a "smarter" cloning tool like Clonezilla, which is also free and open source.