TM4C1294的mac address修改后如何重写?

我使用了Uniflash对TM4C1294芯片进行mac address的写入，写完后想要使用

MAP_FlashUserSet(0x00FFFFFF, 0x00FFFFFF);
MAP_FlashUserSave();

进行修改但是无法达成，查询后知道这两个暂存是一次性的写入（如下），需要使用Uniflash做unlock的动作

These registers each provide 32 bits of user-defined data that is non-volatile. Bits can only be
changed from 1 to 0. The reset value shown only applies to power-on reset when the register is not
yet committed; any other type of reset does not affect this register. Once committed, the register
retains its value through power-on reset. The only way to restore the factory default value of this
register is to perform the "Recover Locked Device" sequence detailed in the JTAG section.

但我在使用Uniflash时无法进行unlock，出现以下错误