Amiga 2000 Buster tower (Commodore 1986)
The Buster tower fixes a buffering bug in the first production run of the Buster chips. Buster is based on the PAL equations of the original German A2000 bus controller logic.
The German PALs contained a bug which did not let the buffers between the 68000 bus and the Zorro bus point away from Zorro when a Zorro bus master talked to a Zorro bus target.
In Germany it was fixed by a replacement PAL, but with the Buster it had to be corrected with the tower.