Dell 3120 Shim process

Question

We've received multiple system boards from Dell for 3120 chromebooks and are unable to use the provided shim tool. It errors out saying invalid action when trying to install it.  I've tried just resetting the serial number on the board and I get an error saying Flashrom is in an unknown state. I've removed the bracket and install the write protect screw and it does not work. I contacted support and the only answer was to send the device in.  I would really like to be able to replace system boards myself as it is a faster repair time. Any suggestions?

anne_droid · Answer

Hi

An internet search offers this...........

To use the Dell RMA shim on a Chromebook 11 3120, the usual flow is: disable write protect, insert the shim USB key, boot into recovery with Esc + Refresh + Power, then follow the on-screen prompts to write the service tag and reload ChromeOS.

What matters for the 3120

Dell’s documented shim process for similar Chromebook models says the shim is used after a system board replacement to restore the Service Tag, VPD, and ChromeOS, and the USB key normally comes with the replacement board or service part. For the 3120 specifically, community reports indicate the RMA shim file is often not publicly posted by Dell, so if you only have the bare file name or a generic USB image, it may not be enough without the correct Dell-issued shim package for that board.

Typical procedure

Remove write protect first, because the shim will not proceed properly if write protection is still enabled.
Plug in the RMA shim USB key.
Hold Esc + Refresh + Power for about 2 seconds to enter recovery/shim boot.
When prompted, continue into the shim installer and complete the service-tag/write process.

Common failure points

Wrong model-specific shim, because Dell shims are board/model specific.
Write protect still enabled.
Using aftermarket or mismatched parts that cause the shim hardware checks to fail, which technicians have reported on other Dell/ChromeOS RMA workflows.

Practical note

If you are trying to repair a Chromebook 11 3120 with no official Dell USB key, the most reliable path is usually the exact board-specific shim package that matches that model and board revision, not a generic ChromeOS recovery image.

ksarnld · Answer

@anne_droid​ Yeah, I've done all that. It seems to be an issue with the 3120's only, I've done 100s of 3100's without issue.  I'm not sure if it's an issue with the shims they are sending or if the write protect screw or flashrom are at fault.

anne_droid · Answer

https://www.dell.com/support/kbdoc/en-us/000209812/chromebook-3110-and-3110-2-in-1-rma-shim-process

Coupla extracts .....

Note: If you are running the RMA Shim after replacing the system board, you do not have to follow the steps below to disable Write Protect.

Replacement system boards are shipped with Write Protect disabled by default.

AND/OR

Note: Some replacement system boards are shipped in Developer Mode and with Write Protect (WP) disabled. Instead of displaying the Recovery Screen, the Chromebook boots from the RMA Shim USB key and load the CrOS Factory Shim setup menu. If you see the CrOS Factory Shim setup menu, then go to Installing the RMA Shim.

Chromebook