155 firmware update

155 softwareLatest versionRelease dateSizeDownload
OS update required
2024-01-1281 MBModel_155.lsfw
Operating system3.0.02024-01-12575 MB


XIP OS update instructions

Firmware update process

This process is not capable of handling a full OS update, which is required for some versions of firmware. See instructions for the update process.

NOTE: OS version 3 and higher requires the firmware to be version 2 and higher.

The easiest way to update instrument firmware is online:

  1. Provide the instrument with an Internet connection using Wi-Fi or Ethernet
  2. Access the update screen (System settings > Update)
  3. The instrument will detect the latest firmware version, follow on-screen prompts to download and install the update

Updating an offline instrument is accomplished with the following steps:

  1. Click on the desired version number below, which links to the .lsfw firmware update file.
  2. Copy or save the .lsfw file onto the root directory of a USB flash drive. Make sure it is the only .lsfw file in that location.
  3. Plug the flash drive into the USB-C port on the back of the instrument; if you don't have a newer flash drive with a USB-C connection, use the adapter supplied with the instrument.
  4. On the 155 front panel, tap the Settings menu (top left corner of the screen). Then tap System settings. Touch Update.
  5. Click “Updates are available. Click here to install” and follow the on-screen instructions to update the firmware.

Note: Firmware comprises many files aggregated to form a Lake Shore firmware (.lsfw) package. The instrument stores versions of its .lsfw packages in its internal memory. This local memory location is called the “local repository.” This allows you to downgrade the firmware to older versions that remain on the instrument in the local repository.

M155 Firmware Changelog

2.0.2023121202 (OS update required) — 24-01-12

Minor bug fixes and housekeeping

1.4.2022022503 — 22-03-03


  • Calibration features only for internal (Lake Shore) use; no user-level impact

1.4.2021062301 — 21-07-14


  • Improved consistency of audible feedback tones
  • Support for new Lake Shore USB-GPIB adapter (MR-GPIB-USB)
  • GPIB terminator detail added to info circle

1.3.2020101401 — 20-10-14


  • Legal page now displays

1.3.2020080303 — 20-08-03


  • Implement Lake Shore optional GPIB adapter compatibility
  • Do not change the output state when settings are reasserted


  • Eliminate carousel images disappearing

1.2.2019080704 — 19-08-07


  • Change default TCP port to 7777 and make configurable


  • Improve output enable transition noise performance
  • Application locking cycling in or out of sleep mode
  • SCPI over TCP setting gets stuck in the off state
  • Exception errors from overlapped commands causing subsequent commands to be rejected
  • SCPI parser exception error handling for overlapping commands

1.2.2018110102 — 18-09-11


  • CPI over TCP communication was still possible when instrument was asleep
  • SCPI over TCP resets to enabled after power cycle

1.2.2018080203 — 18-08-28


  • All digital ref out
  • User settable phase compensation


  • Ethernet shows static IP when actually DHCP on fresh OS install

1.1.2018051008 — 18-05-22


  • Layout of the main menu drawer improved


  • AC commands being accepted in DC only instrument
  • Two dialog boxes created when double tapping on listview item

[1.0] — First release