skiboot-5.1.9 was released on October 30th, 2015.
skiboot-5.1.9 is the 10th stable release of 5.1, it follows skiboot-5.1.8 (which was released October 19th, 2015).
Skiboot 5.1.9 contains all fixes from skiboot-5.1.8 and is a minor bug fix release, with a single fix to help diagnosis after a rare error condition.
Over skiboot-5.1.8, we have the following change:
opal/hmi: Signal PRD about NX unit checkstop. We now signal Processor Recovery & Diagnostics (PRD) correctly following an NX unit checkstop
minor fix to the boot_test.sh test script