GW4
The Samsung Galaxy Watch 4 (LTE) is a round smartwatch that is one of the first ones to contain a bioelectrical impedance analysis (BIA) sensor.
| Model number | SM-R860, SM-R870, SM-R880, SM-R890 (Wi-Fi only), SM-R865U, SM-R875U, SM-R885U, SM-R895U (USA, LTE model), SM-R895F (Int., LTE model) |
| Memory | 1.5 GB |
| Storage | 16 GB |
| SoC | Exynos W920 dual core 1.18 GHz; GPU: Mali-G68 |
| Sensors |
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| Battery | Non-removable 247mAh / 361mAh |
Miscellaneous hardware docs
Manually getting into Download or Recovery Mode
Press and hold both buttons until the "Rebooting..." screen appears. Release both buttons and press the power button (red outline) 3 times.
The reboot menu should be displayed. Press the power button to cycle between the options and confirm the selection with a long press (3 seconds).
Skipping initial setup
The pairing and setup of the watch can be skipped by pressing and holding down the Wear OS logo on the pairing screen.
Debugging and Jigs
The device probably exposes a UART via the USB pads if ID is connected to GND with a 619k resistor. This is currently untested.