Intel has confirmed that lower-end 400 series chipsets namely B460 and H410, will not be compatible with its Rocket Lake-S desktop CPUs. Higher-end Z490 and H470 chipset boards, though, will support the 11th-gen chips with new compatible firmware that Intel and motherboard vendors have started rolling out.
On Intel's official site, the company has listed links to vendors' sites so users can visit and check the compatibility of their boards. For example, so far some like ASUS has clearly stated that their Z490 boards are compatible with Rocket Lake; however, others like ASRock, or MSI are yet to update their motherboards' CPU compatibility lists even though they have launched the compatible BIOSes for Rocket Lake-S CPUs.
Hence, owners of Z490 and H470 chipset motherboards who are looking to upgrade to Rocket Lake-S are encouraged to visit the support section of the motherboard models they own and check for the latest BIOS' descriptions, which should highlight the necessary information of whether the BIOS supports the 11th-gen Rocket Lake CPUs or not. You could also perform a quick Google search with the name of the particular motherboard model you own with a "support" written at the end. This should generally lead to the support page of that particular model where you will find relevant information related to the 11th-gen compatible BIOS you're looking for.
Despite both 400 series and 500 series chipsets being on socket LGA1200, Intel may feel that power delivery designs on the lower end H410 and B460 boards are not up to the task of handling the new Rocket Lake chips, as leaks like this one from a Chiphell forum thread alleges that a Core i9-11900KF hit 98°C even on a 360mm AIO Liquid Cooler. There could also be technical issues holding the firmware updates back, like limited ROM size on the lower end boards. Updating the BIOS is generally also a tricky part for casual users who buy these entry-level boards and may end up bricking their motherboards entirely in the process. Well, whatever be the actual reason, Intel probably feels it's best to avoid the firmware update situation entirely on the H410 and B460 chipsets.
Rocket Lake-S is based on Intel's Cypress Cove micro-architecture which claims to deliver double-digit IPC gains over the previous gen. It is built upon Intel's infamous 14nm process which the firm has been struggling to get past for years.