Hi nos1989,
Debug breakpoint is no relationship with freertos.
The ARM Cortex-M0 in LPC4357 can support 2 instruction breakpoints, but you need to use JTAG debug mode.
You can find this information in the LPC4357 user manual:

Please check your debug interface, and try again.
If you still have question, please tell me the detail step how reflect your problem, I will test it on my side.
Have a great day,
Kerry
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