AHB transfer on Cortex-M3

Hi,

I am running following code in Cortex-M3.

    asm("      MOV R1,#0xFF0");
    asm("      MOVT R1,#0xFFFF");

    asm("      MOV R4,#0xAA0");
    asm("      MOVT R4,#0xAAAA");
    
     //start address
     asm("      MOV R3,#0x0000");
     asm("      MOVT R3,#0x2018");

   
    //end address : 1kB address
    asm("      ADD R2,R3,#0x40");

    //writes
    asm("BACK: STM R3!,{R1,R4}");
    asm("      CMP R2,R3");
    asm("      BHI BACK");

As per AHB, when multi-burst operation such as NONSEQ-SEQ happens, the HBURST should NOT be 0 (SINGLE). But with this, I see HBURST =0.

Is that allowed?