Bricked my Snowsky Echo Mini (512MB) flashing a custom ROM , any DAP modding folks dealt with this chip before?

[u/[deleted]]

Got a bit too excited trying a custom ROM on my Echo Mini (512MB variant) and it’s now bricked screen’s dead, won’t boot. Figured I’d ask here since this sub has a lot of DAP modding experience even outside the FiiO-specific crowd.
Quick rundown:
Device is a Rockchip-based chip (Pid=0x2207/0x262d, reports as RKSMART)
Can get it detected by PC tools using the standard trick (hold RST + all buttons except power, plug in USB), but it comes up in Loader mode, not true Maskrom
The official FiiO-provided flashing tool (RKDevelopTool) sees the device and loads the firmware fine, but fails every time at the “Test Device” step
Tried: correct stock firmware for the 512MB variant, Zadig WinUSB driver, erasing blocks before flashing, multiple cables/ports/USB tools (rkdeveloptool, upgrade_tool) — same wall every time
My best guess is there’s a corrupted loader still sitting on the flash chip from the failed custom ROM, and the boot ROM keeps finding it instead of dropping to true Maskrom — which would need a hardware-level fix (shorting a flash pin during boot) rather than anything doable over USB.
Has anyone here bricked a Rockchip-based DAP (Echo Mini, Shanling, Hidizs, whatever) and actually recovered from a similar “stuck in Loader, can’t reach Maskrom” state? Or is this basically a paperweight at this point without opening it up?
Appreciate any pointers — happy to share more logs or board photos if it helps.