I have a Willow AM4 motherboard. I want to upgrade to a Ryuzen 5 1600. I want to know if this is possible and do I have to update the BIOS to do it.
According to HP Willow Motherboard specs, No it won't support a Ryzen. It supports upgrades of 3 processors all APUs: HP Desktop PCs - motherboard specifications, Willow | HP® Customer Support
Since it is a AM4 socket Motherboard, Ryzen Processors will fit in there without any issues. But without a proper BIOS update to support and recognize the Ryzen Processors, it won't boot up since it won't be recognized by BIOS.
The above are the only processors supported by Willow Motherboards. You can always open a HP Support ticket and ask them if they have an updated BIOS that will support Ryzen processors.