diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -3,3 +3,22 @@
 Library and demos for the Apple-1 TMS9918 video card by P-LAB.
 
 
+# Building for the "Juke Box" EPROM expansion
+
+The demo contained in the repo are meant to be launched from the Apple-1 "Juke Box"
+EPROM expansion at address $4000. The executables are built according to the
+following memory map:
+
+$0000-$00FF zero page: holds most of C program variables
+$0280-$0FFF low RAM space: C program "Data" segment
+$4000-$7581 EPROM (Juke Box): C program "Code" segment
+$7582-$7FFF EPROM (Juke Box): C program "Data" segment (startup values)
+
+The build script "mkeprom.js" creates a 16K binary file to be placed on the
+EPROM where the "Data" segment startup values are put at the end of the file itself.
+The user program need to manually copy such data from EPROM to low RAM once after
+the `main()` is launched. That can be easily done by simply calling the library
+function `apple1_eprom_init()`.
+
+
+