Although Amstrad is the current propietary of the copyright of the original
ZX Spectrum ROMs, they have kindly given their permission for its
redistribution with Spectrum emulators.

These are the conditions put by Amstrad to use and distribute the ROM files,
extracted from
http://groups.google.com/group/comp.sys.amstrad.8bit/msg/c092cc4d4943131e

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1) What exactly do you have to do to use Sinclair ROMs in an emulator, such
as acknowledgements etc?"

Amstrad are happy for emulator writers to include images of our copyrighted
code as long as the (c)opyright messages are not altered and we appreciate
it if the program/manual includes a note to the effect that "Amstrad have
kindly given their permission for the redistribution of their copyrighted
material but retain that copyright".

"2) Can you charge a shareware fee for an emulator that uses the Sinclair
ROMs?"

No. No one should be charging for the ROM code because (as a result of the
point above) there are loads of freely available images anyway. If I ever
thought someone was charging for the ROM images then I'd make them available
as a free download on the www.amstrad.com web site. Naturally I imagine that
some emulator writers want to charge a shareware fee for the code they have
written and we have absolutely no problem with that as long as they aren't,
in any sense, charging for the parts of the code that are (c)Amstrad and (c)
Sinclair.

"3) Can you modify the ROMs, for instance to enable tape loading and saving,
and if so what are the requirements?"

The ROM code is simply a tool to let the emulator writers make a program
that works as close to the original machine as possible. If they choose to
modify the behaviour in any way then that's entirely up to them (I guess you
could say that that is exactly what an emulator IS doing (ie modifying the
screen output and keyboard input to go via the PC bits)!!)

"4) Can you distribute modified ROMs?"

If you like (with that (c) proviso).