An LPC1751 is programmed using CRP1, but Flash Magic (http://www.flashmagictool.com/) shows the CRP is disabled and can read the memory contents.

[lpcware-support]

Early versions of the LPC1751 microcontrollers did not support CRP. These devices can be identified with Part ID 25001110 and with date codes prior to 1013. Newer LPC1751 devices with part ID 25001118 have the CRP feature implemented. An Errata sheet has been created in this regard. The errata sheet can be downloaded from nxp.com​.