MSI is introducing new "MAX" versions of its AMD 400-series chipset based motherboards. As was reported yesterday, MSI struggled with making its 300-series and 400-series motherboards compatible with the new Zen 2-based Ryzen 3000 series because many of these boards have a an EEPROM chip of just 16MB and that turned out to be too small to implement the latest AMD AGESA microcode update.
As such, MSI saw itself forced to cut various features from its UEFI, including SATA RAID support. The motherboard maker is now re-releasing many of its motherboards with a 32MB chip.
The PurePC report states that MSI will brand the revised motherboards "MAX" in the product name (eg: B450 Gaming Pro Carbon AC MAX, B450M Bazooka MAX, etc.), although we don't know if the new model names will have the company's latest MEG/MPG/MAG prefixes. The 256 Mbit SPI flash ROM chip allows MSI to cram in AGESA 184.108.40.206a, which lets you use 3rd generation Ryzen processors to their full capabilities (barring PCIe gen 4.0 on these motherboards of course). More importantly, the larger ROM chip allows MSI to have AGESA 220.127.116.11a without sacrificing on its feature-rich Click BIOS 5 UEFI setup program, SATA RAID module, or losing support for any of the socket AM4 processors.
AMD's cheaper 500-series chipsets aren't expected until early 2020 so the 400-series remains a popular option for enthusiasts who don't want to pay $170 or more for a board with the X570 chipset.