diff --git a/libsrc/atari/system_check.s b/libsrc/atari/system_check.s
index 2f1feefc4..df55f3d13 100644
--- a/libsrc/atari/system_check.s
+++ b/libsrc/atari/system_check.s
@@ -68,8 +68,32 @@ cont:   ldx     #0              ; channel 0
 
 .segment        "SYSCHK"
 
+        rts     ; for older DOSes which unconditionally run the first load chunk
+
 .ifdef __ATARIXL__
 
+; check for SpartaDOS and its usage of RAM below ROM
+; return CF 0/1 for bad/ok
+sdcheck:lda     DOS
+        cmp     #'S'
+        bne     sdcrts0         ; not SpartaDOS, assume RAM is not used
+        lda     DOS+1           ; SD version
+        cmp     #$40            ; SD-X has $40 or higher
+        bcc     sdcrts1         ; older versions (except maybe 1.x) always use the RAM under the ROM
+        ldy     #31             ; offset for OSRMFLG
+        lda     (DOSVEC),y      ; get OSRMFLG
+        bne     sdcrts1
+        
+sdcrts0:clc
+        rts
+sdcrts1:sec
+        rts
+
+ramrom_txt:
+        .byte   "Memory under ROM is in use.", ATEOL
+        .byte   "Cannot run this program.", ATEOL
+ramrom_txt_len = * - ramrom_txt
+
 lmemerrxl_txt:
         .byte   "Not enough memory to move screen", ATEOL
         .byte   "memory to low memory. Consider using", ATEOL
@@ -94,8 +118,13 @@ syschk: lda     $fcd8           ; from ostype.s
 
         jmp     mem_err
 
-sys_ok:
-        .include "xlmemchk.inc"         ; calculate lowest address we will use when we move the screen buffer down
+sys_ok: jsr     sdcheck         ; check for SpartaDOS-X, and if found, whether it uses the RAM under the ROM
+        bcc     sd_ok
+
+        print_string2 ramrom_txt, ramrom_txt_len
+        jmp     fail
+
+sd_ok:  .include "xlmemchk.inc" ; calculate lowest address we will use when we move the screen buffer down
 
         lda     MEMLO
         cmp     lowadr