Increase NVRAM

Hello,

I'm using an IPC227G with a S7-1507S-F and i'm facing retain memory insufficiency.

I had to put NVRAM because if it's using disk space when power goes down, all data is gone. But the NVRAM only has 135kB of size. I found the following sentence:

A total of 512 kB retentive memory NVRAM (Non Volatile RAM) is available.

The software controller can write 135 kB of user data within the buffer time of the IPC.

Is there any way to increase the NVRAM amount to more than 135kB?

What is the point of having 512kB if only 135kB is available?

It appears the 135kb is a limitation of the software controller, not the IPC.

Please see below