https://www.geeky-gadgets.com/msi-amd-400-series-motherboards-10-07-2019/
 
MSI inadvertently erred in giving many of its AMD 400-series chipset motherboards 128 Mbit (16-megabyte) SPI flash ROM chips instead of larger 256 Mbit (32-megabyte) ones, which nearly jeopardized the company's "Zen 2" support deployment, forcing it to greatly thin its motherboard firmware feature-set, and break SATA RAID support on many of its boards. To be fair to MSI, the company may not have anticipated the AGESA microcode growing tremendously in size with its latest ComboAM4 1.0.0.3-series. We are now hearing from Polish tech publication PurePC that MSI has scrambled to remedy this by re-releasing many of its AMD 400-series chipset motherboards with larger 256 Mbit SPI flash ROM chips. 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 1.0.0.3a, which lets you use 3rd generation Ryzen processors to their full capabilities (barring PCIe gen 4.0 on these motherboards of course). 
 
Of course in my opinion that leaves customers who bought motherboards with the 128Mbit rom chips in a bit of a pickle. 
 

hmm thanks for the info my Gigabyte k7 has dual 128mbit chips wonder if thats why some who upgraded the m2 slot cant be seen