ILCE-7RM4: remote auto-transfer hangs (red LED stuck, 0 bytes, no downloadComplete) — capture-to-card works

[AdamYoung66]

Environment

• Camera: Sony ILCE-7RM4 (A7R4)
• @alpha-sdk/api v1.0.9 (npm), CameraWebApp 3.0.0, Sony CRSDK V2.02.00
• Host: Debian 13.6 (trixie), kernel 6.1.0-52-amd64
• USB: negotiated 480Mbps (High Speed), direct to motherboard USB3 port
• usbfs_memory_mb: 16 (default) → also tested with 150 (issue Linux setup: usbfs_memory_mb default (16MB) is far below Sony's required 150MB and is undocumented #45), no change

Symptom

Connection mode remote works: discovery, connect, live view (single frame 162KB received), property get/set, remote shutter all succeed.

BUT with still-image-store-destination = 0x3 (Host PC & Memory Card):

• Remote shutter returns success, image IS written to SD card, but NO file ever arrives on the host
• Camera access LED stays solid red (stuck), playback navigation locks
• Zero bytes / zero downloadComplete SSE events / nothing lands in the save-info path
• Session degrades: subsequent connects fail with "Failed to connect to camera", requires a physical battery-pull reset to recover

With still-image-store-destination = 0x2 (Memory Card only):

• Everything stable: shoot → image on SD → connection stays healthy indefinitely

Reproduction

1. Connect remote mode, PUT save-info to a writable dir
2. PUT still-image-store-destination = 0x3
3. POST /actions/shutter → success, but no downloadComplete, camera red LED stuck

Notes

• compatibility.md lists ILCE-7RM4 as R / — / — (no C, no T). Remote-mode auto-transfer (OnCompleteDownload → downloadComplete) appears to be the only file path, but it hangs on this body.
• Related: RemoteTransfer full-size download silently never completes and latches the whole subsystem into 0x8D03 #40 (0-byte transfer latch), SDK ReleaseDevice() hangs forever after a stuck transfer — server cannot exit, camera needs a physical replug #41 (ReleaseDevice hang), Linux setup: usbfs_memory_mb default (16MB) is far below Sony's required 150MB and is undocumented #45 (usbfs_memory_mb)
• Capture One / Lightroom tethering on the same body works on macOS (different protocol stack), suggesting the camera hardware is fine.

Question

Is remote-mode auto-transfer actually supported on ILCE-7RM4 in CRSDK V2.02.00? If yes, is there a known workaround for the hang? If no, please document it clearly so integrators don't assume remote mode implies file transfer.