hubersn: Emulators should be OK: there are plenty of them that almost certainly don't have the OK - Archie, Sleeve, QEMU, and many more, for example.
There's also the interesting fact that there are no patents at all on the ARM instruction set used in earlier Acorn machines, nor copyrights, as Acorn made them publically available for free before ARM even existed. They get around this with the might of money - see the DEC StrongARM (which used no ARM patents or IP at all, and the design didn't involve ARM in the slightest) or the NEC FPGA/ASIC clone used in the 3DO console that ARM just ended up buying instead.)
RISC OS Firefox port in bug fix update The seventh release of the open source port of Firefox, which uses version 18.104.22.168 of the web browser's source code, is now available for download for Iyonixes, A9homes, Omegas and VirtualRiscPC users. 21 comments, latest by Spriteman on 9/1/09 11:50PM. Published: 1 Jan 2009