So here's basic code for the Micro:bit for handling a SH1106 display, just in case anybody needs it:

import microbit
class SH1106:
    move = bytearray(b'\x00\xb0\x02\x10')
    def __init__(self):
        self.buffer = bytearray(1024)
        microbit.i2c.init(freq=400000, scl=microbit.pin2, sda=microbit.pin1)
        for i in range(2):
            # First two transaction after init always fail.
            try:
                microbit.i2c.write(0x3c, b'')
            except OSError:
                pass
        microbit.i2c.write(0x3c, b'\x00\xae\xd5\x80\xa8\x3f\xd3\x00\x40\x80\x14'
                b'\x20\x00\xa1\xc0\xa0\xda\x12\x81\xcf\xd9\xf1\xdb\x40\xa4\xa6\xaf')
        
    def show(self):
        index = 0
        buf = self.buffer
        for page in range(8):
            self.move[1] = 0xb0 | page
            microbit.i2c.write(0x3c, self.move)
            microbit.i2c.write(0x3c, b'\x40' + buf[index:index + 128])
            index += 128

    def pixel(self, x, y, color=None):
        if not 0 <= x < 128 or not 0 <= y < 64:
            return
        page = y // 8
        index = x + page * 128
        mask = 1 << (y % 8)
        if color is None:
            return bool(self.buffer[index] & mask)
        elif color:
            self.buffer[index] |= mask
        else:
            self.buffer[index] &= ~mask

 This is the naive approach of updating the whole screen every time. It's probably fast enough for most use cases.