diff --git a/SheepShaver/src/emul_op.cpp b/SheepShaver/src/emul_op.cpp
index ba5de77f..2efe04ff 100644
--- a/SheepShaver/src/emul_op.cpp
+++ b/SheepShaver/src/emul_op.cpp
@@ -409,6 +409,16 @@ void EmulOp(M68kRegisters *r, uint32 pc, int selector)
 			r->d[0] = (uint32)-7887;
 			break;
 
+		case OP_CHECK_SYSV: {		// Check we are not using MacOS < 8.1 with a NewWorld ROM
+			r->a[1] = r->d[1];
+			r->a[0] = ReadMacInt32(r->d[1]);
+			uint32 sysv = ReadMacInt16(r->a[0]);
+			D(bug("Detected MacOS version %d.%d.%d\n", (sysv >> 8) & 0xf, (sysv >> 4) & 0xf, sysv & 0xf));
+			if (ROMType == ROMTYPE_NEWWORLD && sysv < 0x0801)
+				r->d[1] = 0;
+			break;
+		}
+
 		case OP_NTRB_17_PATCH:
 			r->a[2] = ReadMacInt32(r->a[7]);
 			r->a[7] += 4;
diff --git a/SheepShaver/src/include/emul_op.h b/SheepShaver/src/include/emul_op.h
index 48cc3e70..5dfa72ed 100644
--- a/SheepShaver/src/include/emul_op.h
+++ b/SheepShaver/src/include/emul_op.h
@@ -47,7 +47,7 @@ enum {	// Selectors for EMUL_OP opcodes
 	OP_ADBOP, OP_INSTIME, OP_RMVTIME, OP_PRIMETIME, OP_MICROSECONDS, OP_PUT_SCRAP, OP_GET_SCRAP,
 	OP_DEBUG_STR, OP_INSTALL_DRIVERS, OP_NAME_REGISTRY, OP_RESET, OP_IRQ,
 	OP_SCSI_DISPATCH, OP_SCSI_ATOMIC,
-	OP_NTRB_17_PATCH, OP_NTRB_17_PATCH2, OP_NTRB_17_PATCH3, OP_NTRB_17_PATCH4, OP_CHECKLOAD,
+	OP_CHECK_SYSV, OP_NTRB_17_PATCH, OP_NTRB_17_PATCH2, OP_NTRB_17_PATCH3, OP_NTRB_17_PATCH4, OP_CHECKLOAD,
 	OP_EXTFS_COMM, OP_EXTFS_HFS, OP_IDLE_TIME, OP_IDLE_TIME_2,
 	OP_MAX
 };
@@ -96,6 +96,7 @@ const uint16 M68K_EMUL_OP_RESET = M68K_EMUL_BREAK + OP_RESET;
 const uint16 M68K_EMUL_OP_IRQ = M68K_EMUL_BREAK + OP_IRQ;
 const uint16 M68K_EMUL_OP_SCSI_DISPATCH = M68K_EMUL_BREAK + OP_SCSI_DISPATCH;
 const uint16 M68K_EMUL_OP_SCSI_ATOMIC = M68K_EMUL_BREAK + OP_SCSI_ATOMIC;
+const uint16 M68K_EMUL_OP_CHECK_SYSV = M68K_EMUL_BREAK + OP_CHECK_SYSV;
 const uint16 M68K_EMUL_OP_NTRB_17_PATCH = M68K_EMUL_BREAK + OP_NTRB_17_PATCH;
 const uint16 M68K_EMUL_OP_NTRB_17_PATCH2 = M68K_EMUL_BREAK + OP_NTRB_17_PATCH2;
 const uint16 M68K_EMUL_OP_NTRB_17_PATCH3 = M68K_EMUL_BREAK + OP_NTRB_17_PATCH3;
diff --git a/SheepShaver/src/rsrc_patches.cpp b/SheepShaver/src/rsrc_patches.cpp
index 9c4ea127..e1a1a8e9 100644
--- a/SheepShaver/src/rsrc_patches.cpp
+++ b/SheepShaver/src/rsrc_patches.cpp
@@ -168,6 +168,12 @@ void CheckLoad(uint32 type, int16 id, uint16 *p, uint32 size)
 					p[5] = htons(0x6010);	// bra
 					D(bug(" patch 7 applied\n"));
 				}
+			} else if (PM(0,0x2f3c) && PM(1,0x7665) && PM(2,0x7273) && PM(3,0x3f3c) && PM(4,0x0001) && PM(10,0x2041) && PM(11,0x2248) && PM(12,0x2050) && PM(20,0x7066) && PM(21,0xa9c9)) {
+				// Check when vers 1 is installed (for safe abort if MacOS < 8.1 is used with a NewWorld ROM)
+				p[10] = htons(M68K_EMUL_OP_CHECK_SYSV);
+				p[11] = htons(0x4a81);	// tst.l	d1
+				p[12] = htons(0x670e);	// beq.s	<SysError #dsOldSystem>
+				D(bug(" patch 9 applied\n"));
 			}
 			p++;
 		}