I’m looking for help with a possibly soft-bricked ZOYI/Zotek ZT-703S oscilloscope multimeter.

Symptoms:

• The device powers on normally
• It immediately enters oscilloscope mode
• The oscilloscope itself still works and reads signals correctly
• However, all front buttons become unresponsive in the main UI

What is interesting:

• The buttons DO work in bootloader/USB mode
• POWER + F1 during startup successfully enters USB mode
• F2 successfully exits USB mode

I also have the known “RAM” USB issue:

• The device appears as “RAM” over USB
• Reduced storage size is shown
• Larger firmware files no longer fit

I already tried multiple official firmware versions, but the issue persists.

After researching EEVBlog and the abandoned open-zt703 project, I suspect:

• corrupted persistent settings/filesystem,
• corrupted internal flash state,
• or a firmware/UI crash when restoring oscilloscope settings at boot.

Important findings:

• The STM32 SWD interface appears to still be enabled
• The open-source project documentation mentions:
  • full chip erase,
  • filesystem recreation,
  • settings reset,
  • and recovery through ST-Link + STM32CubeProgrammer

At this point I’m considering buying an ST-Link V2 and attempting recovery through SWD.

Before I do that, I wanted to ask:

• Has anyone successfully recovered a ZT-703S from this exact state?
• Is there a known way to reset only the settings/filesystem area?
• Does a full chip erase also destroy the original bootloader permanently?
• Has anyone dumped the original flash/bootloader?

Any advice would be greatly appreciated.


Video demostration https://www.youtube.com/shorts/B2H7HaynO...

⟐ Answered June 21, 2026 at 11:33 MST

⟐ Answered September 18, 2025 at 12:01 MST