ALDR-AIX is not booted with the normal re-IPL code,as a normal re-IPL would initialize memory and the HPT contents, destroying all the data needed for performing diagnosis of the crashed OS. For this, we defined a new boot type in PHYP which allows us to re-use and customize LPAR initialization routines to activate ALDR-AIX without a re-IPL. Finally, PHYP loads the initial registers’ values manufactured for the single-threaded ALDR-AIX into the primary thread of VP0. All other hardware threads are kept in a state where they do not execute any instruction from the failed LPAR.