skiboot 6.6.6 was released on Wednesday September 29, 2021. It replaces skiboot-6.6.5 as the current stable release in the 6.6.x series.
It is recommended that v6.6.6 be used instead of v6.6.5 version due to the bug fixes it contains.
Bug fixes included in this release are:
phb4: Disable TCE cache line buffer