The UART peripheral clock seems to be sporadically set to wrong value when the CPU clock is changed. In this case, the UART clock is not set to 115.200 kbps but to 96 kbps, so that the output in the console seems like garbage. This can also cause automatic tests to fail. Therefore, the CPU clock is only changed if CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ defines a different default CPU clock than the one already used at boot time.
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