Yes, sort of. Basically a tiny loader in OTP that enables nCS1 on some pin, copies code from there to ram on nCS0, reconfigures nCS1 to point to second ram. This does break usb flashing. Use swd.
>>dmitry+(OP)
Is there no way to do that without code in OTP? The bootrom is supposed to scan for an IMAGE_DEF on both memory banks, and can use nCS1 as specified in FLASH_DEVINFO. Unless there's something I'm missing, that should be sufficient.