Upgrade path for Dell M640 on VRTX Chassis

from the release notes: https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=g3kmg&oscode=wst14&productcode=poweredge-m640p

starting at line 614: 
Installation Procedure
615 ======================
616
617 1) In the CMC web interface, click Chassis Overview, and then click Update.
618 2) On the Firmware Update page, in the CMC Firmware section, select the required
619 components under the Update Targets column for the CMC or CMCs (if standby
620 CMC is present) you want to update, and then click Apply CMC Update.
621 3) In the Firmware Image box, enter the path to the firmware image file on the
622 management station or shared network, or click Browse to browse through to
623 the file location. The default name of the CMC firmware image file is
624 vrtx_cmc.bin.
625 4) Click Begin Firmware Update, and then click Yes. The Firmware Update Progress
626 section displays information about the firmware update status.
627
628 For more information, see the Chassis Management Controller for PowerEdge VRTX
629 User's Guide available at the support site.
630
631 VRTX Update Procedure
632 =====================
633
634 Prerequisites
635 -------------
636
637 * iDRAC web interface for each server node must be accessible from the
638 management station.
639 * Local or remote access to OS management for each server node.
640 * VRTX chassis CMC web interface must be accessible from management station.
641 * All server and chassis components must be in a Healthy state with no
642 outstanding issues or alerts. Any issues must be resolved prior to
643 performing updates.
644
645
646 Server Node Updates
647 ===================
648
649 Visit dell.com/support and download the latest available Windows DUP versions of
650 the following programmable components for the server node model (M520, M620,
651 M630, M820, or M830) used in the VRTX chassis to be updated:
652
653 * BIOS
654 * iDRAC7/8
655 * CPLD
656
657 Also, download the latest available Shared PERC8 driver for the operating system
658 installed on the server node.
659
660 Note: If the OS is VMWare ESXi, the driver is part of the Dell ESXi image.
661
662
663 --------------------------------------------------------------------------------
664 Updating Server Nodes
665 --------------------------------------------------------------------------------
666
667 1) Update the operating system-specific Shared PERC8 driver on all the server
668 nodes. For Windows operating system, see the Shared PERC8 User’s Guide
669 available at dell.com/support. For VMware, the driver is part of the
670 Dell-customized ESXi image.For more information, see installing async drivers
671 at kb.vmware.com.
672 2) Update the iDRAC firmware using Windows DUP and the iDRAC web interface for
673 each server node, or on all server nodes at once through VRTX CMC web
674 interface if Enterprise license is in place and the Extended Storage feature
675 is enabled. This update takes several minutes to complete after which, the
676 iDRAC web interface becomes inaccessible for approximately three minutes.
677 3) Update the CPLD on each server node using the Windows DUP and iDRAC web
678 interface. Make sure to select “Install and Reboot” after uploading the DUP,
679 which forces the server nodes to reboot and perform the CPLD update. After the
680 CPLD update completes a complete server node power cycle occurs. This results
681 in the iDRAC web interface being inaccessible for approximately three minutes.
682 4) Update the BIOS on each server node using Windows DUP and the iDRAC web
683 interface. You can also update the BIOS on all server nodes at once through
684 the VRTX CMC web interface -- Server Overview -> Update tab, if the Enterprise
685 license is in place. Make sure to select “Install and Reboot” after uploading
686 the DUP, which forces the server nodes to reboot and perform the BIOS update.

#Iwork4dell

in the release notes for the CMC: https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=g3kmg&oscode=wst14&productcode=poweredge-m640p
Starting at line 614:
Installation Procedure
615 ======================
616
617 1) In the CMC web interface, click Chassis Overview, and then click Update.
618 2) On the Firmware Update page, in the CMC Firmware section, select the required
619 components under the Update Targets column for the CMC or CMCs (if standby
620 CMC is present) you want to update, and then click Apply CMC Update.
621 3) In the Firmware Image box, enter the path to the firmware image file on the
622 management station or shared network, or click Browse to browse through to
623 the file location. The default name of the CMC firmware image file is
624 vrtx_cmc.bin.
625 4) Click Begin Firmware Update, and then click Yes. The Firmware Update Progress
626 section displays information about the firmware update status.
627
628 For more information, see the Chassis Management Controller for PowerEdge VRTX
629 User's Guide available at the support site.
630
631 VRTX Update Procedure
632 =====================
633
634 Prerequisites
635 -------------
636
637 * iDRAC web interface for each server node must be accessible from the
638 management station.
639 * Local or remote access to OS management for each server node.
640 * VRTX chassis CMC web interface must be accessible from management station.
641 * All server and chassis components must be in a Healthy state with no
642 outstanding issues or alerts. Any issues must be resolved prior to
643 performing updates.
644
645
646 Server Node Updates
647 ===================
648
649 Visit dell.com/support and download the latest available Windows DUP versions of
650 the following programmable components for the server node model (M520, M620,
651 M630, M820, or M830) used in the VRTX chassis to be updated:
652
653 * BIOS
654 * iDRAC7/8
655 * CPLD
656
657 Also, download the latest available Shared PERC8 driver for the operating system
658 installed on the server node.
659
660 Note: If the OS is VMWare ESXi, the driver is part of the Dell ESXi image.
661
662
663 --------------------------------------------------------------------------------
664 Updating Server Nodes
665 --------------------------------------------------------------------------------
666
667 1) Update the operating system-specific Shared PERC8 driver on all the server
668 nodes. For Windows operating system, see the Shared PERC8 User’s Guide
669 available at dell.com/support. For VMware, the driver is part of the
670 Dell-customized ESXi image.For more information, see installing async drivers
671 at kb.vmware.com.
672 2) Update the iDRAC firmware using Windows DUP and the iDRAC web interface for
673 each server node, or on all server nodes at once through VRTX CMC web
674 interface if Enterprise license is in place and the Extended Storage feature
675 is enabled. This update takes several minutes to complete after which, the
676 iDRAC web interface becomes inaccessible for approximately three minutes.
677 3) Update the CPLD on each server node using the Windows DUP and iDRAC web
678 interface. Make sure to select “Install and Reboot” after uploading the DUP,
679 which forces the server nodes to reboot and perform the CPLD update. After the
680 CPLD update completes a complete server node power cycle occurs. This results
681 in the iDRAC web interface being inaccessible for approximately three minutes.
682 4) Update the BIOS on each server node using Windows DUP and the iDRAC web
683 interface. You can also update the BIOS on all server nodes at once through
684 the VRTX CMC web interface -- Server Overview -> Update tab, if the Enterprise
685 license is in place. Make sure to select “Install and Reboot” after uploading
686 the DUP, which forces the server nodes to reboot and perform the BIOS update.

#Iwork4Dell

It is always recommended to perform staged update by keeping all these three firmware in sync based on release year. You can skip some version in between. Below could be one order for update

CMC - 3.30

iDRAC - 4.00.00.00

BIOS - 2.4.8

CMC - 3.40

iDRAC - 5.00.00.00

BIOS - 2.11.2