Dvmm 191 Upd May 2026

The DVMM 191 UPD is not backwards compatible with all hardware revisions.

| Hardware Revision | Compatible? | Notes | | :--- | :--- | :--- | | Rev A (2009-2012) | No | EEPROM is too small (64kb). Update will fail at 78%. | | Rev B (2013-2018) | Yes | Requires manual buffer clear after install. | | Rev C (2019+) | Yes | Fully compatible; supports rollback. | dvmm 191 upd

To check your hardware revision, look at the silkscreen on the PCB near the mounting hole: DVMM-191-RevX. The DVMM 191 UPD is not backwards compatible

Cause: The UPD requires a higher current capacity than the old firmware. If your PSU is rated below 500mA, the module browns out. Solution: Upgrade your power supply to a 12V @ 1A minimum. Update will fail at 78%

Prior to the update, the module required a strict 9600 baud rate. With the DVMM 191 UPD, the module now auto-negotiates rates between 9600 and 115200 baud, reducing communication time by 40%.