Based on the IBM Technote: Capturing Boot Debug
Changing to debug mode in the boot image
bosboot -I -ad /dev/hdiskXFrom the Open Firmware prompt:
AIX 5.2
boot -s trapAIX 5.3 ~ 7.1
boot -s verboseUsing the KDB prompt:
Debug boot:
0> mw enter_debug0> gResuming normal boot:
0> quitAIX alog debug boot log
/tmp/boot.debuglog