Ahh fair enough. In any case, with the help of @Fox_exe, it looks like he also managed to reproduce the booting into the myCloud device by means of the special ping (although he used a method using WinPCap; I’m also using a Windows environment which is really convenient this is possible, but would have been happy to manage via a Linux Guest).
Given that it is indeed possible to browse the filesystem on the BusyBox ramfs environment, was it ever possible to mount the full hard disk itself? Although there are no issues mounting /dev/md126 or /dev/md127 which houses the device’s flash memory holding the OS and such, it didn’t look like any of the /dev/sda# partitions would play ball with mount.
Currently, without opening up the physical enclosure, I’m trying to investigate the means of tracing what is happening at standard boot (somehow my device decided to isolate itself from being visible on the LAN - even after adding the eth0 entry back into /etc/network/interfaces)
Looking in BusyBox on the MyCloud via Telnet, I can see the following:
/mnt # fdisk -l
fdisk: device has more than 2^32 sectors, can't use all of them
Found valid GPT with protective MBR; using GPT
Disk /dev/sda: 4294967295 sectors, 4095M
Logical sector size: 512
Disk identifier (GUID): e322dd27-e54e-4065-8de8-045fa0b3be00
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Number Start (sector) End (sector) Size Code Name
1 1032192 5031935 1953M 0700 primary
2 5031936 9031679 1953M 0700 primary
3 30720 1032191 489M 0700 primary
4 9428992 5860532223 2790G 0700 primary
5 9031680 9226239 95.0M 0700 primary
6 9226240 9422847 96.0M 0700 primary
7 9422848 9424895 1024K 0700 primary
8 9424896 9428991 2048K 0700 primary
Disk /dev/md127: 2047 MB, 2047803392 bytes
2 heads, 4 sectors/track, 499952 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk /dev/md127 doesn't contain a valid partition table
Disk /dev/md126: 2047 MB, 2047803392 bytes
2 heads, 4 sectors/track, 499952 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk /dev/md126 doesn't contain a valid partition table
So essentially the flash memory partitions are visible and read/writable, but not the physical 3TB disk itself on /dev/sda4. Mounting just gives the usual “Device Busy” EDIT: Looks like /dev/sda4 finally decided to mount after all. Wonder why it didn’t work previously… :\
It does look like some things are manageable. If it may, dd could possibly work for injecting img but I’m still not sure if the Device or resource busy messages would have an implication for those partitions whilst unmounted.
Launching ftpd via tcpsvd works, which makes things somewhat manageable to pass files in and out.
EDIT2: dd works. Unbricking mycloud on BusyBox environment via Telnet successful! 
