So, I have successfully downgraded from OS 5, to OS 3. It took some hours of trial and error to find that nothing worked as easy as it should have. In the end, the resolution was to destroy the root file system, which makes the machine boot into safe mode. Once in safe mode, OS 3 installed and rebooted pretty as you please, and all functions have returned to normal while data remains intact on the NAS.
root@MyCloudEX2Ultra # cat /proc/mtd
[ 1.224605] 0x000000000000-0x000000500000 0: “U-Boot”
[ 1.230172] 0x000000500000-0x000000a00000 1: “uImage”
[ 1.235582] 0x000000a00000-0x000000f00000 2: “uRamdisk”
[ 1.241139] 0x000000f00000-0x00000c800000 3: “image.cfs”
[ 1.247693] 0x00000c800000-0x00000d700000 4: “rescue fw”
[ 1.253357] 0x00000d700000-0x00000eb00000 5: “config”
[ 1.258813] 0x00000eb00000-0x00000f500000 6: “reserve1”
[ 1.264386] 0x00000f500000-0x00000ff00000 7: “reserve2”
root@MyCloudEX2Ultra # nandwrite /dev/mtd3 rootfs.cfs (extracted from OS 3 bin file)
Writing data to block 0 at offset 0x0
Writing data to block 1 at offset 0x20000
Writing data to block 2 at offset 0x40000
Writing data to block 3 at offset 0x60000
Writing data to block 4 at offset 0x80000
Writing data to block 5 at offset 0xa0000
Writing data to block 6 at offset 0xc0000
Writing data to block 7 at offset 0xe0000
Writing data to block 8 at offset 0x100000
Writing data to block 9 at offset 0x120000
Writing data to block 10 at offset 0x140000
[ Truncated to save space ]
Writing data to block 790 at offset 0x62c0000
Writing data to block 791 at offset 0x62e0000
Writing data to block 792 at offset 0x6300000
Writing data to block 793 at offset 0x6320000
Writing data to block 794 at offset 0x6340000
Writing data to block 795 at offset 0x6360000
Writing data to block 796 at offset 0x6380000
Writing data to block 797 at offset 0x63a0000
root@MyCloudEX2Ultra # reboot
After rebooting, the status light was flashing blue, and the HDD lights flashing red and blue. Loading the webui, shows the device is in safe mode and request the fw file to be loaded. At this point, it does not check to see that the fw is at least OS 5, which allows for the downgrade of the OS back to OS 3.
After initial setup and enabling SSH, I am now prompted with the following:
BusyBox v1.20.2 (2019-07-04 10:46:34 CST) built-in shell (ash)
Enter ‘help’ for a list of built-in commands.
root@MyCloudEX2Ultra sbin # chk_fw_ver
old firmware ver:1.01.004.1005.2015
new firmware ver:2.40.157.1015.2020
fw_split:[1.01.004.1005.2015]
fw_split:[2.40.157.1015.2020]
—tok_old:[1] tok_new:[2]
major=1,minor=1,sub=4
model name:MyCloudEX2Ultra
chk_fw_ver: wd2go.sh flag=[1] cmd=[wd2go.sh -p]
Orion is set for the Production Server::
root: hostname=MyCloudEX2Ultra
root@MyCloudEX2Ultra sbin # read_version -a
firmware version: 2.40.157(2.40.157.1015.2020)
u-boot version : U-Boot 2013.01_v1.04 (Aug 20 2015 - 11:11:32) Marvell version: 2014_T3.0p6
mcu version: 1.06
rescue_fw_version: 1.01.004.1005.2015
root@MyCloudEX2Ultra root # dmesg | grep mtd
[ 7.857491] UBI: attaching mtd5 to ubi0
[ 7.918004] UBI: attached mtd5 (name “config”, size 20 MiB) to ubi0
[ 29.432354] UBI: attaching mtd6 to ubi1
[ 29.525170] UBI: attached mtd6 (name “reserve1”, size 10 MiB) to ubi1
[ 30.737081] UBI: attaching mtd7 to ubi2
[ 30.772039] UBI: attached mtd7 (name “reserve2”, size 10 MiB) to ubi2
root@MyCloudEX2Ultra root # cat /proc/mtd
dev: size erasesize name
mtd0: 00500000 00020000 “U-Boot”
mtd1: 00500000 00020000 “uImage”
mtd2: 00500000 00020000 “uRamdisk”
mtd3: 0b900000 00020000 “image.cfs”
mtd4: 00f00000 00020000 “rescue fw”
mtd5: 01400000 00020000 “config”
mtd6: 00a00000 00020000 “reserve1”
mtd7: 00a00000 00020000 “reserve2”
