Hello Denis,
I didn't like what Debug did with your int2etst.dbg (512 bytes),
so I had A86 assemble it. 17 bytes. QEMM took exception.
Tried without QEMM and got your results.
    * Note to A86 users *
Added mov ss,cs and A86 gave no error but changed the code "behind my back"
to push cs  pop ss  which of course did not work!
(yes I know, mov ax,cs/mov ss,ax)
Here is what I sent to A86.
Mov     Bx,0200h        ;DOS:set memory block size
Mov     Cl,04           ; BX=paragraphs
Shr     Bx,Cl           ; ES=block seg
Inc     Bx              ; BX=para avail
Mov     Ah,4ah          ; ret if error
Int     21h
Mov     Si,0080h
Int     2eh             ;DOS Internal
nop
nop
mov     ss,cs       ;should be via ax.  A86 assembled this as push cs/pop ss
mov     sp,0fffeh
mov     ah,4ch
int     21h
Kind regards, Barry 
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