The decompression for the program is as follows:

int srcPos; /* start at the end of the packed exe, because the unpacker works downwards */
int dstPos;
int commandByte, lengthWord, fillByte;

/* skip all 0xff bytes (they're just padding to make the packed exe's size a multiple of 16 */
while (*srcPos == 0xff) {
srcPos--;
}

/* unpack */
do {
commandByte = *(srcPos--);

switch (commandByte & 0xFE) {
/* (byte)value (word)length (byte)0xb0 */
/* writes a run of <length> bytes with a value of <value> */
case 0xb0:
lengthWord = (*(srcPos--))*0x100;
lengthWord += *(srcPos--);
fillByte = *(srcPos--);
for (i = 0; i < lengthWord; i++) {
*(dstPos--) = fillByte;
}
break;
/* (word)length (byte)0xb2 */
/* copies the next <length> bytes */
case 0xb2:
lengthWord = (*(srcPos--))*0x100;
lengthWord += *(srcPos--);
for (i = 0; i < lengthWord; i++) {
*(dstPos--) = *(srcPos--);
}
break;
/* unknown command */
default:
printf("Unknown command %x at position %x\n", commandByte, srcPos);
exit(1);
break;
}
} while ((commandByte & 1) != 1); /* lowest bit set => last block */