--- a/doc/User-phone-tools	Tue Jan 15 06:01:04 2019 +0000
+++ b/doc/User-phone-tools	Wed Jan 16 01:21:29 2019 +0000
@@ -70,7 +70,7 @@
   via a built-in CP2102 or FT232R chip.
 
 * As a dirty hack, one can run FreeCalypso GSM fw on some alien hw targets,
-  currently Motorola C139 and Pirelli DP-L10.  In this hacked-up configuration
+  currently Motorola C1xx and Pirelli DP-L10.  In this hacked-up configuration
   there is no dedicated UART available for a standard AT command interface, but
   there is a hack that allows a limited subset of AT commands to be passed over
   the RVTMUX binary packet interface provided by the running FreeCalypso GSM fw.
@@ -78,11 +78,25 @@
 
 The AT-over-RVTMUX mechanism was originally invented back in 2015 as a
 development aid, and was never intended for production use or to support any
-kind of end user functionality.  One of its limitations is that the strings
-that are sent to ATI via this interface are limited to 254 characters, whereas
-sending or writing SMS in hex format requires longer strings.  As a result, SMS
-sending and writing functionality via fcup-smsend* is limited when a crippled
-Motorola or Pirelli hw target is used instead of proper FreeCalypso hardware.
+kind of end user functionality.  One of the limitations of its original
+incarnation was that the strings that are sent to ATI via this interface were
+limited to 254 characters, whereas sending or writing SMS in hex format
+requires longer strings.  As of early 2019, this limitation has been lifted:
+our Magnetite and Selenite firmwares from 20190109 onward support an extended
+version of our AT-over-RVTMUX hack that allows longer strings to be sent in
+pieces, and the present version of our FC User Phone Tools suite will send the
+strings it generates via this extended mechanism whenever they exceed the old
+254 character limit.  However, please be aware that FC firmware for Mot C1xx
+phones is still a purely unsupported offering for the sake of the community, it
+is NOT our main project direction, and this fw configuration does *not* receive
+the same level of development support and testing as our FCDEV3B modem product.
+A test of SMS sending functionality via the newly extended AT-over-RVTMUX
+interface on a Mot C139 phone using our current (as of this writing) 20190109
+firmware revealed that something is still broken, and we do not currently have
+a business case to justify allocating more developer time to investigate those
+issues.  In contrast, our FCDEV3B modem running our current 20190112 firmware
+is rock solid, and all SMS functions work flawlessly going through the standard
+AT command interface on the dedicated UART.
 
 All fcup-* tools take the following common command line options for selecting
 the AT command target interface:
@@ -209,6 +223,13 @@
 Composing and sending outgoing SMS
 ==================================
 
+[2019 update: this section has not yet been updated for the new reality that
+ sending maximum-length SMS in PDU mode over RVTMUX is now possible, but please
+ see the earlier notes about this functionality still not working quite right
+ when tested on a Mot C139 phone.  Until further updates, please stick to using
+ PDU mode over the classic AT command channel over the dedicated UART on
+ FCDEV3B hardware.]
+
 When used with a FreeCalypso GSM device that offers the full AT command
 interface (currently only the FCDEV3B modem), the primary SMS sending/writing
 tool fcup-smsend offers the following capabilities: