>... it is board for a steering wheel for gaming ...
First, I assume you considered and checked the legality of your endeavour, as it is a commercial product.
> ... I even tried by removing the LPC part ...
I don't know if this makes sense. But if the SWD, Mode and ISP pins are accessible, I would avoid it, since it puts additional stress on the MCU, and might damage it.
However, the datasheet has the following to say :
There are three levels of Code Read Protection:
1. CRP1 disables access to the chip via the SWD and allows partial flash update
(excluding flash sector 0) using a limited set of the ISP commands. This mode is
useful when CRP is required and flash field updates are needed but all sectors cannot
be erased.
2. CRP2 disables access to the chip via the SWD and only allows full flash erase and
update using a reduced set of the ISP commands.
3. Running an application with level CRP3 selected, fully disables any access to the chip
via the SWD pins and the ISP. This mode effectively disables ISP override using
PIO0_1 pin as well. If necessary, the application must provide a flash update
mechanism using IAP calls or using a call to the reinvoke ISP command to enable
flash update via the USART.
After checking the board is still functional at all, I would inspect it for access to the Mode and ISP pins.
Although I would be surprised if this is successful.
The MCU itself is relatively cheap, and such gaming equipment not designed for repair in general. A throw-away product, in other words.
To keep competitors from reverse-engineering it, most companies activate the highest security level (aka CRP), which denies both SWD and system bootloader access. In other words, CRP level 3 in this case.
There are ways to circumvent that, which usually raise the involved costs by 2 or 3 orders of magnitude.
