diff --git a/README.md b/README.md
index 14db294..c812677 100644
--- a/README.md
+++ b/README.md
@@ -23,3 +23,26 @@ makes [SWO viewing as simple as connecting to a serial port](https://github.com/
 See online documentation at https://github.com/blacksphere/blackmagic/wiki
 
 Binaries from the latest automated build are at http://builds.blacksphere.co.nz/blackmagic
+
+BLACKMAGIC
+==========
+
+You can also build blackmagic as a PC hosted application
+"make PROBE_HOST=hosted"
+
+This builds the same GDB server, that is running on the Black Magic Probe.
+While connection to the Black Magic Probe GDB server is via serial line,
+connection to the PC-Hosted GDB server is via TCP port 2000 for the first
+GDB server and higher for more invokations. Use "tar(get) ext(ented) :2000"
+to connect.
+PC-hosted BMP GDB server can talk to the Black Magic Probe itself,
+ST-LinkV2 and V3, CMSIS-DAP, JLINK and FTDI MPSSE based debuggers.
+
+When connected to a single BMP supported probe, starting "blackmagic" w/o any
+arguments starts the server. When several BMP supported probes are connected,
+their types, position and serial number is displayed and the program exits.
+Add "-P (position)" to the next invokation to select one.
+
+PC hosted BMP also allows to flash, read and verify a binary file, by default
+starting at 0x08000000. The "-t" argument displays information about the
+connected target. Use "-h " to get a list of supported options.