Ensoniq SQ-1 OS v1.01 EPROM Firmware Upgrade Update for SQ1


Ensoniq SQ-1 OS v1.01 EPROM Firmware Upgrade Update for SQ1

SKU: FW-86 Category: Tags: , ,


Ensoniq SQ-1 – Final OS revision update/upgrade: Version 1.01

This is firmware update 1.01 and is the latest official released operation system by Ensoniq Corp. This operation system update/upgrade requires two eprom chips as revealed in the article`s photos and the chips will be labeled to help you locate the correct chip socket. For more info, please check below.

Check current firmware:

Press Edit Sequence and hold it until you see the Edit LED turned on but not blinking, While holding down System (Bank 9), quickly press Screen 1, The display should now read “ENSONIQ SQ-1 OS Version X.XX”


You need the swap the eprom chips in socket UPPER and LOWER.


  • Upgrade version 1.01 contains a vast amount of bug fixes as well as new additions, far too many to list below but I’ll make an attempt at listing a few noteworthy fixes and additions:
  • Unexpected event #33 could be caused by rapidly selecting sounds in select sound mode. This has been fixed.
  • The following sounds have been modified to reduce effect noises: 00 Grand Act, 10 Piano & Strings, 12 Clarinet, 17 String Section, 38 Slam Guitar, 39 Chuk Guitar. A few others were also modified to correct minor voicing problems.
  • The Edit Sequence button no longer waits for the second half of a double-click after keeping the first track recorded from Edit Sequence mode after being in Edit Sequence Flashing mode.

This upgrade is not compatible with the SQ-1 Plus.