RFU
Pinout
| Pin | Description |
|---|
| 5 | firmware flash ~W (write protect) |
| 6 | firmware flash C (clock) |
| 7 | firmware flash ~S (chip select) |
| 8 | firmware flash Q (data out) |
| 9 | firmware flash D (data in) |
| 10 | firmware flash ~Reset |
| 2,18,30,32 | VSS |
| 28 | VCC |
Write protect of firmware flash can be pulled high by shorting the SL1 pads located next to the battery. The access hole is covered by a white sticker with red dots.