Is it required to have HSE clock source for custom bootloader using CAN bus for STM32F446RE

[HSing.2]

Hello,

In the application note AN2606, it is mentioned that ST's bootloader for STM32F446RE requires HSE clock if CAN bus is used to upload the hex file.

Now, if I am writing my own custom bootloader to upload the code via CAN, would I still need the HSE clock. Is possible to route HSI clock for the system clock and APB1

Thank you.

Snippet from AN2606

[Tesla DeLorean]

You can choose to clock it via any source you want, even ones which are out-of-spec. As long as you're willing to deal with things not work on an occasional unit, and support of that, you can use the HSI