I just received a Grove Beginner Kit and while testing out Lesson 7: “Displaying data on the OLED” the text “Hello World!” displays on screen but every other pixel line in the display is blank - it looks like the characters are displaying double-height with every other line of pixels blank.
Edit: I managed to get the Adafruit_SSD1306 library working on the Grove Beginner Kit and am seeing all the expected pixels - every other line is NOT blank, so the hardware is good.
Edit - Fix: I was able to get the text to render correctly (without the extra blank pixel lines) by changing the example in lesson 7 to use U8X8_SSD1306_128X64_NONAME_HW_I2C instead of U8X8_SSD1306_128X64_ALT0_HW_I2C.