EliteBook 840 G6 docks: exact G2, UltraSlim and G5 choices

Which dock options should you consider?

For HP EliteBook 840 G6, use HP Thunderbolt Dock 120W G2 (2UK37AA) when you need the strongest documented native display path: HP exact-lists it and caps this host at three displays total, so keep no more than two external screens when the notebook panel is active. Use the UltraSlim Docking Station (D9Y32AA) when a mechanical side connector and dual DisplayPort desk are preferable. HP USB-C Dock G5 (5TW10AA) is also exact-listed and later HP firmware names this model, but its exact G6 combined-resolution table is not published; treat it as the simpler port-convenience option rather than assuming triple external or dual-4K modes. The notebook's 45 W or 65 W adapter class is below the G2/G5 up-to-100 W delivery ceiling, while fast charge requires a qualifying 65 W path.

Connect displays and power

G2 host cable

Power the dock with its HP 120 W adapter, then connect its supplied Thunderbolt cable directly to the notebook's single USB-C/Thunderbolt 3 port.

G2 displays

For the conservative two-external 4K60 route, connect one display to dock DisplayPort and the second through the rear Thunderbolt port with a correctly rated USB-C/Thunderbolt-to-DisplayPort path. Keep the notebook panel as the third total display.

UltraSlim displays

Seat the notebook on the side docking connector and use both dock DisplayPort outputs for the documented dual-2560×1440-at-60-Hz arrangement.

G5 displays

Connect its captive USB-C host lead directly and begin with one rear DisplayPort or HDMI output. Do not transfer G5's generic DSC or triple-output ceilings to this exact older host.

Power

The notebook was configured with 45 W or 65 W adapters. G2 and G5 can negotiate up to 100 W to supported hosts; HP fast charge needs a qualifying 65 W path and is not proof of docked performance.

First recovery steps by symptom

Thunderbolt Dock G2 is not detected

1. Check the dock's rear white adapter LED; HP says it requires a valid HP 19.5 V 120 W-or-larger adapter.
2. Sign in with appropriate local rights and approve the HP Thunderbolt Dock G2 when the Thunderbolt prompt appears, then reconnect the host cable.
3. If still absent, shut down, disconnect host and dock power for five seconds, reconnect dock power first and test one USB device before adding displays.

USB works but a display is blank

1. Reduce the desk to one monitor, select its exact input and press Windows+P to choose Extend or Second screen only.
2. Use a documented G2, G5 or UltraSlim output with a cable rated for the requested mode; begin at FHD60.
3. Compare the notebook's direct HDMI path, which HP limits to 4K30, before updating the exact host BIOS, graphics components and dock firmware.

USB-A devices disappear at startup or in BIOS

1. Disconnect the dock and confirm the device directly after Windows starts.
2. Install the current exact-model BIOS; HP's affected-model advisory requires R70 01.22.00 or later for this USB-C-hub startup issue.
3. Reconnect one device at a time and keep dock firmware current without unplugging the dock during its update.

Charging is slow or absent

1. Verify the dock's matching HP adapter, rear LED and supplied host cable, then remove high-draw accessories.
2. Compare direct charging with the notebook's original 45 W or 65 W HP adapter.
3. If direct power works, update the exact dock firmware and notebook BIOS; remember that a 45 W path does not meet HP's fast-charge condition.

Still unknown: HP does not publish an exact USB-C Dock G5 combined-resolution table for this G6 host. Exact monitor EDIDs, cables, mixed refresh and color depth, HDR, DSC support, MST adapters, lid-closed behavior, Radeon 550X routing, Windows 11 validation of the 2019 display table, Linux or FreeDOS software behavior, sleep/wake stability and field reliability remain unknown. No notebook, dock or monitor was tested by Connect Your Dock.

Compare documented options · Check screens and power

Applies to the standard HP EliteBook 840 G6 in QuickSpecs c06308183. It does not transfer to the Healthcare Edition, 846 G6 or another EliteBook generation. Sources reviewed 21 September 2026. Manufacturer documentation is not a Connect Your Dock hardware test.