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Firmware · 2025-10-17

Uniden SDS100 firmware 1.23.20 main

Verified — manufacturer file

Download zip (2.1 MB) Manufacturer's page ↗

Main firmware 1.23.20 (17 October 2025). It enhanced squelch control for WFM/FMB, fixed NAC display in System Status mode and during P25 Phase 2 voice, and added a menu for switching headphone audio output phase.

Read before installing. Uniden's change log says main 1.23.20 REQUIRES sub 1.03.15 or later, and sub 1.03.15 is not in this package (it is delivered only by Sentinel). Install this file only on a scanner whose sub firmware is already 1.03.15, i.e. one that Sentinel has updated to 1.23.20 or later. Posted by Uniden in December 2025 for stepping back from 1.24.00. Uniden's readme spells the file "SDS100_V1_23_20.bin"; the file is SDS-100_V1_23_20.bin.
Product
SDS100 firmware
Version
1.23.20 main
Released
2025-10-17
Runs on
Any PC that can copy files to a USB mass-storage device (Uniden's steps use Windows Explorer)
Applies to
Uniden SDS100
Zip SHA-256
fdb468027b4dca57afe46fbc5c9759a47199f839a4acf382ed5838e98b98ece2

Contents

FileSizeSHA-256
SDS100_V1.23.20_Main.zip2.1 MB2b45fa6ab3c0efb8f3babae26a2011ea7f8e68fcf40b8a8a0426f76358b50ef8
README.txtThese instructions
SHA256SUMSChecksums of the files above

Instructions

The complete README.txt included in the zip:

Uniden SDS100 firmware 1.23.20 main
===================================

WHAT THIS IS
Main firmware 1.23.20 (17 October 2025). It enhanced squelch control for
WFM/FMB, fixed NAC display in System Status mode and during P25 Phase 2 voice,
and added a menu for switching headphone audio output phase.

IMPORTANT: Uniden's change log says main 1.23.20 REQUIRES sub 1.03.15 or
later, and sub 1.03.15 is not in this package (it is delivered only by
Sentinel). Install this file only on a scanner whose sub firmware is already
1.03.15, i.e. one that Sentinel has updated to 1.23.20 or later. Posted by
Uniden in December 2025 for stepping back from 1.24.00. Uniden's readme spells
the file "SDS100_V1_23_20.bin"; the file is SDS-100_V1_23_20.bin.

Uniden normally delivers firmware only through Sentinel (UPDATE -> Update
Firmware), which always installs the newest version. Uniden published this
package on its change-log page so that owners can install this specific
version by hand - in practice, to go back to it. To bring a scanner up to
date, use Sentinel instead.

APPLIES TO
The Uniden SDS100 (US model) only. Every firmware file carries the model name
(SDS-100_...). Do not use it on the SDS200, SDS150, BCD436HP or BCD536HP. The
European SDS100E uses separately named firmware files (e.g.
SDS100E_V1_23_09.bin, per RadioReference owners) and must not be given these
files.

BEFORE STARTING
  - A Windows PC. Uniden's instructions use Windows Explorer; the scanner
    appears as an ordinary removable disk.
  - The mini-USB data cable, in the mini-USB port on the side of the scanner
    (the one marked Charge, not the micro-USB port).
  - A fully charged battery (Uniden's readme asks for this), or the scanner on
    USB charge.
  - A backup: copy the whole microSD card to the PC and save the Favorites
    Lists in Sentinel first (Uniden's readme asks for both).
  - Sub firmware 1.03.15 already on the scanner. Check under Menu -> Settings
    -> See Scanner Information -> Firmware Version. If the sub is older,
    update with Sentinel instead.

CONTENTS OF THIS ZIP
The download zip holds the vendor file exactly as Uniden published it, plus
this README.txt and SHA256SUMS.

  SDS100_V1.23.20_Main.zip  (2164663 bytes)
    SHA-256 2b45fa6ab3c0efb8f3babae26a2011ea7f8e68fcf40b8a8a0426f76358b50ef8

  Inside SDS100_V1.23.20_Main.zip:
    SDS100 V1.23.20 Main/Readme SDS100 V1_23_20.txt
      Uniden's own instructions (downgrade to 1.23.20)
      2118 bytes
      SHA-256 035500101ce190e7e43d93d8786b205e88cce3e97d7b2a7c6c1ec3db7bec98b7
    SDS100 V1.23.20 Main/SDS-100_V1_23_20.bin
      main (CPU) firmware 1.23.20
      2162688 bytes
      SHA-256 d5e59d125c06f1f9885c6d09bca5040ac5f1f479bcd2550afb7d75471fed9e88

INSTALLATION
  1. Turn the scanner on.
  2. Connect it to the PC with the USB cable. The scanner shows "USB Cable
     Detected / Select USB mode" with "Mass Storage = E" and "Serial Port =
     .".
  3. Press E (Yes) to choose Mass Storage. The scanner shows "USB Mass
     Storage".
  4. In Windows Explorer, open the new removable disk, then the "BCDx36HP"
     folder, then its "firmware" folder. It already holds CitiTable_V00_00.dat
     and ZipTable_V00_00.dat - do not touch or delete them.
  5. Unzip the download on the PC and copy SDS-100_V1_23_20.bin into the
     "firmware" folder. Only one main (.bin) and one sub (.firm) file may be
     in the folder at a time; with several versions present the update will
     not start or will load incorrectly.
  6. Restart the scanner ("reset the power", in Uniden's words). The update
     starts automatically as it boots. Do not turn the scanner off until the
     update has finished.
  7. When it has finished, the scanner deletes the firmware file(s) from the
     "firmware" folder by itself.

VERIFYING
Menu -> Settings -> See Scanner Information -> Firmware Version shows the main
and sub versions now installed. The firmware file(s) will also have gone from
the card's "firmware" folder.

IF SOMETHING GOES WRONG
  - Update did not start: check that only one main and one sub file are in the
    "firmware" folder and that the file names are exactly as supplied.
  - Scanner will not start properly after files were deleted from the
    "firmware" folder: the two .dat files were probably removed. Uniden's
    remedy is Sentinel -> Clear User Data, which rebuilds the card but erases
    all user data (hence the backup).
  - USB connection fails or is slow: take the microSD card out and use a card
    reader; Sentinel can work on the card directly (see Vol 5 on this site).
    The same folder layout applies.
  - Card errors: back up what is readable, format the card with the SD
    Association's SD Memory Card Formatter (cards up to 32 GB), run Sentinel
    -> Clear User Data, then Update Firmware.
  - Uniden does not document a recovery procedure for an update interrupted by
    power loss; this could not be confirmed from any source. Uniden's readme
    closes with "Please use these files on your risk."

DOWNGRADING
This package exists for going back: Uniden's readme covers moving from 1.24.00
or later, with the sub staying at 1.03.15. To return to the current version
afterwards, run Sentinel -> UPDATE -> Update Firmware.

PROVENANCE
  - Official source:
    https://info.uniden.com/twiki/pub/UnidenMan4/SDS100FirmwareUpdate/SDS100_V1.23.20_Main.zip
  - Listed on:
    https://info.uniden.com/twiki/bin/view/UnidenMan4/SDS100FirmwareUpdate
  - Wayback copy:
    https://web.archive.org/web/20260101200248/https://info.uniden.com/twiki/pub/UnidenMan4/SDS100FirmwareUpdate/SDS100_V1.23.20_Main.zip
  - Retrieved: 2026-09-18. Status: verified (downloaded from Uniden's own
    server; SHA-1 matches the Wayback capture).

MORE INFORMATION
  - scanners.fubsypoly.com, Uniden SDS100 - Vol 5, Upgrades & Firmware:
    https://scanners.fubsypoly.com/uniden-sds100/vol-5/
  - Reference Library, SDS100 Owner's Manual:
    https://scanners.fubsypoly.com/library/uniden-sds100-original-manual/
  - Reference Library, Easier to Read SDS100/SDS200 Manual:
    https://scanners.fubsypoly.com/library/easier-to-read-sds100-200-manual/
  - Uniden change log:
    https://info.uniden.com/twiki/bin/view/UnidenMan4/SDS100FirmwareUpdate

Other versions of SDS100 firmware

← All Uniden SDS100 downloads