# EFI Shell at boot

**URL:** <https://forum.universal-robots.com/t/efi-shell-at-boot/17484>\
**Category:** Technical Questions\
**Created:** [November 8, 2021, 5:53pm UTC](https://forum.universal-robots.com/t/efi-shell-at-boot/17484 "2021-11-08T17:53:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![anon2495229](https://avatars.discourse-cdn.com/v4/letter/a/a8b319/32.png) [@anon2495229](https://forum.universal-robots.com/u/anon2495229)\
**Post date:** [November 8, 2021, 5:53pm UTC](https://forum.universal-robots.com/t/efi-shell-at-boot/17484/1 "2021-11-08T17:53:34Z")

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Hi,

I am using UR3 in my PhD studies. After unpluging and repluging a USB device on the control box, I am encountering with an “EFI Shell - Device mapping table” at booting the device as in the image below.

 ![20211108_164554](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/5/505e9de757c67dbf31ac23a055300800065b1e23.jpeg)

I can give you more information if it is needed, but basically I had removed a USB plug of an Robotiq Gripper or Sensor to plug in a mouse, which worked in my first boot but after I rebooted this problem occurred.

As a result I can’t boot up the device anymore. Is there an easy solution for this or should I contact with technical support?

Thanks.

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**Author:** ![mmi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/mmi/32/691_2.png) [@mmi](https://forum.universal-robots.com/u/mmi)\
**Post date:** [November 11, 2021, 7:54am UTC](https://forum.universal-robots.com/t/efi-shell-at-boot/17484/2 "2021-11-11T07:54:27Z")

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Likely OS partition was corrupted.  
There is full os image available on download site. However this should be done by advanced Linux users only (tech support primarily).  
Preferably calibration data should be recovered from corrupted flash drive before re-flashing.

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**Author:** ![mschlegel](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@mschlegel](https://forum.universal-robots.com/u/mschlegel)\
**Post date:** [September 18, 2023, 3:27pm UTC](https://forum.universal-robots.com/t/efi-shell-at-boot/17484/3 "2023-09-18T15:27:47Z")

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After reflashing new OS, the shell error still occured.

BUT I was able to type in ‘exit’ to the SHELL command and it booted to Polyscope

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**Author:** ![trent1](https://avatars.discourse-cdn.com/v4/letter/t/a587f6/32.png) [@trent1](https://forum.universal-robots.com/u/trent1)\
**Post date:** [March 28, 2024, 3:41pm UTC](https://forum.universal-robots.com/t/efi-shell-at-boot/17484/4 "2024-03-28T15:41:03Z")

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I have had the same exact experience. Technical support says the motherboard needs replaced. But for now I will keep the keyboard plugged in and type ‘exit’ to save $1,000.