RKPalmUSB — Palm Desktop WinUSB drop-in transport

A drop-in replacement for Palm Desktop's USBPort.dll that talks to Palm OS handhelds through Microsoft's in-box winusb.sys instead of the obsolete Palm/Aceeca kernel driver. HotSync works on Windows 11 with Memory Integrity and Secure Boot left enabled.

Palm Desktop binaries are not modified. The only kernel-mode USB driver involved is Microsoft's signed winusb.sys.

Hotsync.exe (32-bit)
   -> USBTransport.dll        Palm SLP/PADP framing, unchanged
      -> USBPort.dll          <- this project (32-bit, WinUSB-backed)
         -> winusb.sys        Microsoft, signed, in-box
            -> Palm handheld

Status

Milestone	State
ABI of the original USBPort.dll recovered	done — docs/usbport-abi.md
Replacement DLL builds, 32-bit, CFG/ASLR/DEP	done
Export table matches the original exactly	done — scripts\Check-Abi.ps1 passes 12/12
Loads in a 32-bit process, exports callable	done — scripts\Test-Load.ps1 passes
WinUSB INF + probe tool	written, awaiting hardware
End-to-end HotSync on a real device	not yet tested — no handheld attached

Everything that can be verified without a Palm has been verified. The device-dependent parts — hardware IDs, endpoint discovery, the handshake — are written from the pilot-link protocol reference and need a real device to confirm.

Quick start

.\scripts\build.ps1            # build USBPort.dll (x86) and palm-usb-probe.exe (x64)
.\scripts\Check-Abi.ps1        # export table must match the original
.\scripts\Test-Load.ps1        # load the DLL in a 32-bit process and call exports

# --- with the handheld plugged in ---
.\scripts\Find-PalmDevice.ps1  # read the hardware ID, paste it into driver\PalmWinUSB.inf
.\scripts\Install-Driver.ps1   # bind the device to winusb.sys (elevated)
.\build\x64\palm-usb-probe.exe list
.\build\x64\palm-usb-probe.exe descriptors
.\build\x64\palm-usb-probe.exe listen     # press HotSync; expect bytes starting BE EF ED

# --- then hand it to Palm Desktop ---
.\scripts\Install-Dll.ps1      # copies into C:\Program Files (x86)\Palm\
.\scripts\Install-Dll.ps1 -Rollback

See docs/installation.md for the driver-signing step, which is the one part that needs a decision from you.

How it works

USBPort.dll sits below Palm's framing layers, so it never needs to understand HotSync. It is a byte pipe with eight meaningful operations: register for device notifications, recognise an arriving Palm, open a port, read, write, set timeouts, close, unregister.

Three details from the reverse engineering drive the implementation:

• Everything is __cdecl with undecorated names and fixed ordinals 1–12.
• PalmUsbReceiveBytes is a buffered stream read. Callers ask for exactly 10 bytes (the SLP header) and poll. WinUSB bulk reads return whole packets, so the DLL buffers a packet internally and hands out byte counts on demand.
• Status 3 means disconnected and only that. USBTransport.dll abandons a session immediately on 3 but retries indefinitely on any other non-zero status, so misreporting a transient error as 3 kills the sync, and misreporting a disconnect as anything else hangs it.

Layout

docs/usbport-abi.md      the recovered ABI, with evidence for every claim
docs/installation.md     driver signing, install, first sync
docs/rollback.md         complete removal
docs/troubleshooting.md  symptom -> cause
evidence/                hashes and dumpbin/disassembly output for the original binaries
src/usbport/             the replacement DLL
tools/palm-usb-probe/    standalone WinUSB test tool
driver/PalmWinUSB.inf    binds Palm hardware IDs to winusb.sys
scripts/                 build, verify, install, roll back
oldusbdriver/            the legacy Aceeca driver package (reference only, never installed)

Scope

Targets Palm Desktop 6.2.2 / HotSync Manager 7.0.2 with a Palm-branded (VID 0x0830) handheld on Windows 11 x64. Other vendors from the legacy INF are listed in driver/hardware-ids.md and can be added one at a time after testing.

Not included: an installer executable, CI, replay/fault-injection tests, or a distribution-signed driver package.

Legal

Contains no Palm, PalmSource, Access or Aceeca code. The replacement DLL is an original implementation written against an ABI recovered from binaries already present on the machine, for interoperability. oldusbdriver/ holds the user's own copy of the legacy package for reference and is never installed or redistributed.