SSD1306 skips every other line

Almost! You should also change the page max in flipCmds from 7 to 3 (but if you're just sending a 128x32 buffer then it still displays ok):

var initCmds = new Uint8Array([ 0xAe, // disp off
             0xD5, // clk div
             0x80, // suggested ratio
             0xA8, C.OLED_HEIGHT-1,
             0xD3,0x0, // display offset
             0x40, // start line
             0x8D,extVcc?0x10:0x14, // charge pump
             0x20,0x0, // memory mode
             0xA1, // seg remap 1 (use 0xA0 to flip horizontally)
             0xC8, // comscandec (use 0xC0 to flip vertically)
             0xDA, (C.OLED_HEIGHT==64)?0x12:0x02,
             0x81,extVcc?0x9F:0xCF, // set contrast
             0xD9,extVcc?0x22:0xF1, // set precharge
             0xDb,0x40, // set vcom detect
             0xA4, // display all on
             0xA6, // display normal (non-inverted)
             0xAf // disp on
            ]);
var flipCmds = [0x21, // columns
     0, C.OLED_WIDTH-1,
     0x22, // pages
     0, (C.OLED_HEIGHT==64)?0x7:0x03];

The only other issue I had with the module was a lack of support for a CS pin. Adding that would be nice.