On the FAQ of the emu48 software, a famous emulator for HP38/39/40/48/49 calculators (https://hp.giesselink.com/emu48faq.htm#ROM), we can find the following assertion:
In general all HP-ROM files are copyrighted by Hewlett Packard. But since fall 2000 HP ACO allowed the use of the HP38, 39, 40, 48, 49 ROM's even if you're not an owner of this calculator type.
And, indeed, you can easily find on the internet (e.g. on the hpcalc.org site) various ROM dumps of the above-mentioned models. Obviously, if HP were offended by this, hpcalc.org would have received a "cease and desist" letter a long time ago.
However, I have been unable to find any reference of an actual announcement from HP on that matter.
Has there been such an official announcement, which details in which condition the ROM codes can be used freely? Or has it been something decided totally informally by HP, who is tolerating ROM code distribution and usage without saying anything?
Note: this seems even more strange if we consider that the HP48 has been discontinued as late as 2003. HP therefore gave the ROM code away before the calculators were out of production, which is rather unusual from a manufacturer.