Lucky7
Description
Lucky7 (Samsung Galaxy Watch FE) is a feature-rich, round smartwatch measuring 40mm developed by Samsung. It released with Android 13, and uses the Exynos W920 (S5E5515) Cortex-A55 based AArch64 SoC. Its hardware is very similar to that of the Samsung Galaxy Watch 4 (codenamed Fresh). See the GSMArena page for more hardware details.
There are two different variants of this watch:
| Codename | Model Number | Model Name | Display Size |
|---|---|---|---|
| lucky7bs | SM-R861 | Samsung Galaxy Watch FE (WiFi) | 40mm |
| lucky7us | SM-R866 | Samsung Galaxy Watch FE (LTE) | 40mm |
Bootloader Unlocking
WARNING: Unlocking the bootloader will trip Knox efuses! Connections inside the SoC will be irreversibly severed, you will permanently lose the ability to use features such as Samsung Pay, and you will get a warning on each startup stating that the device's software "may be corrupt" (this can be ignored).
NOTE: If the device is running OneUI 8 (Android 16) or later, you might not be able to unlock the bootloader. Samsung completely removed bootloader unlocking from its phones globally, and are likely to have done so for their watches too (although this has not yet been verified). If you are on OneUI 7 (Android 15) or below, DO NOT UPDATE.
The bootloader of the Galaxy Watch FE can be unlocked with the following steps:
- Open settings.
- Go to "About watch" -> "Software information"
- Tap the software version several times until you are informed that developer mode has been enabled.
- Locate the "OEM unlocking" option in the developer options menu, and switch it on.
- Hold both buttons on the side of the watch until the Samsung logo appears with the "rebooting..." text below it.
- Quickly press the upper button several times to open the bootloader menu.
- Use the upper button on the side of the watch to navigate to the "Bootloader unlock" option and select it. A short click moves to the next option and a long hold selects an option.
- Follow any instructions presented to unlock the bootloader.
- After rebooting, if you end up in the recovery, follow the steps presented to wipe the device's data.
- Your bootloader is now unlocked.
Repair
This watch is relatively easy to disassemble to repair. There are four Y00 screws on the back, then everything else just pulls apart.
It uses a rubber gasket for water resistance, so as long as it isn't damaged during disassembly it should be able to be reused, and water resistance not compromised.
See the Samsung Galaxy Watch 4 iFixit repair guides for detailed steps for various repairs.
USB
There are no USB connections exposed anywhere on the exterior of this watch. There are however internal USB pads near the top edge of the watch, which can have a USB cable soldered onto them.
The pinout, with the top edge facing towards you, is as follows from left to right:
- Vcc
- ID
- D+
- D-
- GND
To connect to the watch over USB, you must connect the ID pin to GND through approximately 150kOhms of resistance (it doesn't have to be exact).