Pressure measurement returns a '0' value. Temperature is OK
This happens on ESP8266-20180511-v1.9.4.bin. On ESP8266-20170823-v1.9.2.bin and previous versions, this was OK.
After reloading one of the previous versions on the ESP, measurement was OK again!
The BMP180 is recognized during the I2C scan and seems to function correctly (sending & receiving over I2C works). Something seems to be changed on the ESP release 1.9.4, causing this failure.