+Allows disk flip autodetection in "The Big Demo" to work
+(disk1 -> empty -> disk2 cycle and the opposite)
+--- atari800-4.2.0/src/sio.c.orig 2019-12-28 18:00:29.000000000 +0100
++++ atari800-4.2.0/src/sio.c 2021-01-14 17:31:08.961358709 +0100
+@@ -1083,7 +1083,9 @@
+ Log_print("Drive Status unit %d %x %x %x %x",unit,buffer[0], buffer[1], buffer[2], buffer[3]);
+ return 'C';
+ }
+- buffer[0] = 16; /* drive active */
++ /* DVSTAT0 bit 4: drive active(?)/motor on;
++ "The Big Demo" expects 0->1 trigger to detect disk insertion after "flip the disk" message */
++ buffer[0] = disk[unit] != NULL ? 16 : 0;
+ buffer[1] = disk[unit] != NULL ? 255 /* WD 177x OK */ : 127 /* no disk */;
+ if (io_success[unit] != 0)
+ buffer[0] |= 4; /* failed RW-operation */