diff --git a/README.md b/README.md
index 933566b..5c2762d 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ More information is available on the [wiki](https://wiki.cuvoodoo.info/doku.php?
 board
 -----
 
-The development board used for this project is a [blue pill](https://wiki.cuvoodoo.info/doku.php?id=stm32f1xx#blue_pill).
+The development board used for this project is a [system board](https://wiki.cuvoodoo.info/doku.php?id=stm32f1xx#system_board).
 This offers a [STM32F103C8T6 micro-controller](http://www.st.com/web/en/catalog/mmc/FM141/SC1169/SS1031).
 
 peripherals
@@ -30,8 +30,6 @@ LED
 - query (yellow): goes on when starting to query the measurement values from all electricity meters, and goes off when it received all values.
 - submit (blue): goes on when it start submitting the values to the database (using an HTTP POST on influxDB), and goes off when the submission succeeded.
 
-Note: don't use the onboard LED on PC13 on the blue pill as switching it heavily influences the RTC.
-
 Connections LED (cathode) <-> board (all LED anodes are connected to the +3.3V rail):
 
 - power; GND
@@ -64,17 +62,6 @@ Connections DDM100TC <-> board:
 - S0+, pin 8; +3.3V or +5V
 - S0-, pin 7; PB6, TIM4_CH1 (add pull-down resistor)
 
-PZEM-004T
----------
-
-This 1-phase 2-wire electricity meter provides a UART interface.
-For the 3-phase 4-wire power distribution installation I used 3 meters, one per phase.
-
-Because each command includes a device address, they can be connected to the same UART port (one individual addresses have been set).
-All meters are periodically (see RTC) sequentially queried for their measurements (voltage, current, power, energy).
-The used addresses are hard coded in `main.c`
-A timer is used to guarantee a minimum (undocumented in the specification) time between requests in order to improve the response success.
-
 Connections 3xPZEM-004T <-> board:
 
 - 5V, 1; +5V (+3.3V is not sufficient)
@@ -125,12 +112,12 @@ The hostname, port, database name, user name, and password are hard coded in `ma
 Connections ESP-01 <-> board:
 
 - GND, pin 1; ground
-- TX, pin 2; PA10, USART1_RX
+- TX, pin 2; PA3, USART2_RX
 - GPIO2, pin 3; not connected
 - CH_PD, pin 4; pull-up resistor
 - GPIO0, pin 5; not connected
 - RST, pin 6; pull-up resistor
-- RX, pin 7; PA9, USART1_TX
+- RX, pin 7; PA2, USART2_TX
 - VCC, pin 8; +3.3V (add a large capacitor to cope with power spikes)
 
 code