Basic Infos

• [ x] This issue complies with the issue POLICY doc.
• [ x] I have read the documentation at readthedocs and the issue is not addressed there.
• [x ] I have tested that the issue is present in current master branch (aka latest git).
• [x ] I have searched the issue tracker for a similar issue.
• [ x] If there is a stack dump, I have decoded it.
• [x ] I have filled out all fields below.

Platform

• Hardware: ESP-12
• Core Version: latest git / 2.5.1
• Development Env: Arduino IDE
• Operating System: Windows

Settings in IDE

• Module: Generic ESP8266 Module
• Flash Mode: dio
• Flash Size: 4MB
• lwip Variant: v2 Lower Memory
• Reset Method: ck
• Flash Frequency: 40Mhz
• CPU Frequency: 160MHz
• Upload Using: SERIAL
• Upload Speed: 115200

As requested in gitter here are the disabled functions:

uint8_t type() {
        return 0;//card.type();
    }
    uint8_t fatType() {
        return 0;//volume.fatType();
    }
    size_t blocksPerCluster() {
        return 0;//volume.blocksPerCluster();
    }
    size_t totalClusters() {
        return 0;//volume.clusterCount();
    }
    size_t totalBlocks() {
        return 0;//(totalClusters() / blocksPerCluster());
    }
    size_t clusterSize() {
        return 0;//blocksPerCluster() * blockSize();
    }
    size_t size() {
        return 0;//(clusterSize() * totalClusters());
    }