Pegasus2 R4 don't work on Mac Studio Monterey Chip M1 Ultra

  • Last Post 31 July 2023
Giorgio Olivero posted this 12 July 2022

Hello. I connected my Pegasus2 R4 (raid1) to my new Mac Studio with M1 ultra chip and OS Monterey. I used Apple original Thunderbolt 3 - to Thunderbolt 2 adapter, but it doesn't load volumes ...

Can someone help me?


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Olivier Klencklen posted this 22 July 2022


j'avais le même problème sur un M1 (Mac Book Pro, Mac mini). Puis sur un M1 pro, on m'a demandé d'installer un driver : R_Promise_Utility_402000012.dmg si je me souviens bien… j'ai accès au disque, mais j'ai toujours un message système de l'os d'Appel qui me dit qu'il ne sera bientôt plus compatible. C'est préoccupant !  


Si quelqu'un à plus d'information à ce sujet, nous sommes preneurs ;-)


Gautham Sakthi posted this 25 July 2022


For the M1 MAC please install the below Promise Pegasus user space driver and check again,

Richard Harris posted this 22 August 2022

Same problem - I've been trying to resolve this with Promise support for more than a year, with no result. I'm close to removing Promise from our list of preferred suppliers for our new data centre build.

R P posted this 22 August 2022

Hi All,

When the M1 macs came out the Pegasus 2 was indeed tested, I know as I tested with the Pegasus 2 myself.

But some investigation has revealed that if the Pegasus has old firmware, like 5.04.0000.17 (FCS release), the Pegasus 2 won't mount on either an Intel or M1 MAC running Monterey. This firmware is from 2013. But when I attached my Pegasus 2 to Catalina it mounted fine. So my testing had obviously been done with the latest firmware.

If the latest Pegasus 2 firmware is loaded (5.04.0000.64) the Pegasus2 will mount on both the M1 (with both the kext and user space driver) and the Intel Monterey. It can be slow to mount, I did not time it, but it might take a minute, then it works fine and can be managed with the latest Pegasus32 Utility.

Since the Pegasus 2 with old firmware won't be recognized by an M1 MAC, a firmware update will have to be done from an older MAC. I used a Catalina MAC Mini, but Big Sur will probably work as well.

R P posted this 19 December 2022


We suggest using the Pegasus user space driver with Ventura or Monterey. Please use the Promise Utility and driver from the Pegasus32, they are backwards compatible with the Pegasus2.

This DEXT driver from the Pegasus32 downloads should be used.

Note that installing this driver will delete the kernel space driver.

The Pegasus 2 firmware was updated in 2020, the latest firmware should be used. But there is an issue with the latest Pegasus32 Promise Utility and it will not update Pegasus2 firmware. But a slightly older Pegasus Utility will work.

Please use this Promise Utility (v4.06.0000.01).

To update with this Pegasus2 firmware (v5.04.0000.64).

Without the latest firmware the Pegasus2 might experience random disconnects and failure to reconnect after a reboot, depending on how old the firmware currently installed is.


Rebecca Firlik posted this 09 January 2023

To update with this Pegasus2 firmware (v5.04.0000.64).

Without the latest firmware the Pegasus2 will experience random disconnects and failure to reconnect after a reboot.

This firmware link is broken. .... 

R P posted this 09 January 2023

Hi Rebecca,

That's odd, it works OK for me.

Try this, the link will be good for 30 days from today.

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Steve RENDOULIS posted this 30 July 2023

  • Hi - I'm trying to use my R4 and R6 with an M2 Mac but without sucess. 

Can you pls explain how I can upgrade the firmware; I'm totally lost.


Pls KISS :)


R P posted this 31 July 2023

Hi Steve,

We have a knowledge base article on this.