I had all kinds of problems navigating HP and HPE’s support site to find the firmware for an HPE ProCurve V1810-48G switch (HP SKU J9660A)
I eventually found it here, and was able to change the model number at the end for other similar products.
https://h10145.www1.hpe.com/downloads/SoftwareReleases.aspx?ProductNumber=J9660A
And HP have broken it again. This now no longer works:
As of March 18, 2022, all software downloads for networking products are only supported in the HPE Networking Support Portal. You can log in or register at https://networkingsupport.hpe.com/