Use a tool like md5sum or sha256sum and compare against known good hashes posted on communities like Reddit’s r/printers or the HP Support Community.
Ensure the file is named exactly hp___.rfu (two underscores) and is in FAT32 root. Try redownloading the file from another source.
Disconnect the printer from your network entirely. Use a USB cable. Without internet access, the printer cannot receive new firmware blocks. This works indefinitely. hp officejet pro 8620 firmware downgrade
Always research a printer’s firmware policy before buying. Search for “[model] third-party ink blocked” before purchase.
for the older, "friendlier" version of the firmware—the one from before the lockout was implemented. Use a tool like md5sum or sha256sum and
: TomatoInk provides a 5-step downgrade guide that explains the general process of using an older .exe firmware file to overwrite current software. Core Steps to Downgrade
Before attempting any downgrade, immediately disable automatic updates: Disconnect the printer from your network entirely
Bricking is rare if you follow instructions precisely. Thousands of users have successfully downgraded the 8620. Still, proceed at your own risk.
“I had 20 compatible cartridges sitting in a drawer after HP pushed the FDP32C update. I followed the USB downgrade to FDP32B using a file from a printer forum. It worked perfectly. I’m back to printing for 2 cents per page.” —
A: Indirectly—by running Windows via Boot Camp or a virtual machine (Parallels/VMware). The USB pass-through must be perfect. Most users find it easier to borrow a Windows PC.