It seems likely but I'm still not entirely convinced.
I can't entirely figure out how much the former Apple engineer quoted there was involved. He clearly knows how the SE firmware is loaded, but I'm not clear about the level of his knowledge from the SE side. The described mechanism of running a signed blob from RAM doesn't exclude some sort of wipe-on-update mechanism, but it would have to be very low level, part of the hardwired secure boot stuff.
The blog post that's quoted afterwards is total speculation and contains no information about this, even though it claims to.
So, probably, but still lacking a properly definitive statement.
I can't entirely figure out how much the former Apple engineer quoted there was involved. He clearly knows how the SE firmware is loaded, but I'm not clear about the level of his knowledge from the SE side. The described mechanism of running a signed blob from RAM doesn't exclude some sort of wipe-on-update mechanism, but it would have to be very low level, part of the hardwired secure boot stuff.
The blog post that's quoted afterwards is total speculation and contains no information about this, even though it claims to.
So, probably, but still lacking a properly definitive statement.