If an infinite loop occurs when the hwclock commnad will be executed, the reason is as follows.
The board version 1.3 that I have, the fuse has not been initialized.
Security configuration in addition to the MAC address was also uninitialized state.
To use internal RTC(snvs_rtc), SEC_CONFIG[0] bit must be set to 1.
https://community.freescale.com/thread/308588Perhaps the Field of SPEED_GRADING[5:4] also not have been set.
Therefore /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq is 792000.