Just before switching to runlevel 3/5 (therefore this should be in rc.sysinit) some process tries to open /usr/lib/rpm/rpmrc. Well, nobody says that /usr is already there then ... if not, the following error is issued: Unable to open /usr/lib/rpm/rpmrc
Found it. it's KERNEL_ARCH=`rpm -q --qf '%{ARCH}' kernel$KERNEL_TYPE`
Yup, should be worked around in initscripts-5.45-1.