422 sounds like the versions that came with an earlier version of 10.15, it seems you should be able to update to the latest version..Do we know which bootrom ver is required? I think mine is at 420 or 422. But I know that the latest is 429 . I can't upgrade mine using the stock SSD since it's dead. Do you think 420/422 bootrom will allow bootrom updates via third party SSD? Thanks
Which EFI firmware should your Mac be using? (version 4)
macOS 10.15 Catalina brings EFI firmware updates for all supported models, and subsequent updates have changed those for most models too. This article lists the firmware versions of Macs which have…
eclecticlight.co
Worst case the genuine Apple drives are fairly cheap (64GB ones should be attained for well under 20; that should be enough to get you by)
Last edited: