diff --git a/86DOS.ASM b/86DOS.A86
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rename to 86DOS.A86
diff --git a/ASM.ASM b/ASM.A86
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diff --git a/BOOT.ASM b/BOOT.A86
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diff --git a/CHESS.ASM b/CHESS.A86
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diff --git a/COMMAND.ASM b/COMMAND.A86
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diff --git a/DOSIO.ASM b/DOSIO.A86
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diff --git a/EDLIN.ASM b/EDLIN.A86
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diff --git a/HEX2BIN.ASM b/HEX2BIN.A86
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diff --git a/RDCPM.ASM b/RDCPM.A86
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diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
Full source code reconstruction of 86-DOS 0.11 - the earliest released version of the earliest operating system for the Intel x86 architecture.
> [!IMPORTANT]
-> All 8086 assembly language source files in this repository should use the extension .A86; however, I have chosen to use the extension .ASM instead because GitHub does not detect .A86 files as assembly. To build the source code under CP/M or Cromemco CDOS, you must rename all .ASM files to .A86.
+> All 8086 assembly language source files in this repository use the extension `.A86`, because 86-DOS was originally assembled using the SCP Z80/8086 Cross Assembler running under Cromemco CDOS. To build 86-DOS under 86-DOS itself or MS-DOS, you would have to rename all `.A86` files to `.ASM`.
## Progress
diff --git a/SYS.ASM b/SYS.A86
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diff --git a/TRANS.ASM b/TRANS.A86
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