IAP Code Size Issue

Hello!

I am using NXP LPC1114/333 (56K flash) with keil 5.

Bootloader starts from 0 and App starts at 0x1000
App works fine when BIN size was smaller than 24,384 Bytes:
Program Size: Code=22604 RO-data=1452 RW-data=1020 ZI-data=1228

But not larger.
And when I set App runs from 0, the flash size limit issue is gone.

Where should I start to get rid of this?

Thank you!

ZQ