The switch selects the upper or lower half of the 32K eprom. The lower half contains the corrected 2068 ROM code, and the upper half contains the corrected Spectrum ROM code.
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Spectrum 32 EPROM version C
The switch selects the upper or lower half of the 32K eprom. The lower half contains the corrected 2068 ROM code, and the upper half contains the corrected Spectrum ROM code.