How to fix this iPhone 5 error NAND? - 1

Today I found that my iPhone has this problem, any idea hot to fix it?!

This is what is written on the screen.

[NAND ] _FindFlashMediaAndKeepout:601 physical nand block offset 1
[NAND ] start:356 this 0x9f538400 PROVIDER=0x9f6b1f00 flashMedia=0x9f6b1f00
[NAND ] WMR_Start: 149 Apple PPN NAND Driver, Read/Write
[NAND ] WMR_Start: 174 FIL_Init [OK]
[NAND ] WMR_Open: 371 VFL_Open [OK]
[NAND ] s_cxt_boot: 88 sftl: error, unclean shutdown; adopted 11280 spans
[NAND ] WMR_Open: 420 FTL_Open [OK]
[NAND ] _publishServices: 642 FTL capabilities: 0x00000001
[NAND ] _ppnvflGetStruct: 3469 Checking borrowed blocks - count: 23 max_count: 23
[NAND ] _fetchBorrowedList: 881 number of borrowed blocks 16

You should go to an Apple service center they will fix it for you, but I am not sure how much it costs.