To use a different ROM
On the Tools menu, click Options.
Click the Advanced tab.
Under Custom ROMs, click the Spectrum model whose ROM you want to change.
Enter the filename of the ROM or use the Browse button (...) to locate the file.
Click OK.
Tip
When you save a zx-state snapshot, the custom ROM is included. You can then clear the custom ROM from the advanced settings page and just load the snapshot whenever you want to use the ROM.
Note
Using custom ROMs tends to break a lot of Spectrum software.
If the ROM file cannot be loaded or is the wrong size (see the table here), Spectaculator will alert you and revert to the standard ROMs.
Auto load is automatically disabled if you have custom ROMs installed since it relies on code in the original ROMs.