[Android General] Juglar:
Thanks indeed, Renate, for your detailed reply.

First of all, I reply you:

Im not much worried about photos, which I had alredy backup up a week before, but about Apps installed and configured, about some files in the file system (I don't remember now which ones could be important) and a little worried about the general setup. It would take me probly months to restore the hundreds of Apps installed and, specially, the bank apps, which could maybe make me pass again by the cumbersome face identification process, as well as not having a list of them all, so I could forget some important one ... So, summing up: I would prefer to lose the phone than its configured and stored data.

I explained myself wrong. I wanted to make sure that writing in EDL mode to partitions different from userdata would not additionally and inadvertentedly wipe the userdata partition or its encryption access keys.

About the slot _a to slot _b copy with your EDL.EXE, right: no need for the HWID.

In effect, I've tried all the edl commands which I've needed with the option /qbc and it works like a charm !

It has allowed me to comfortably and swiftly read and write partitions by name and by blocks.

That way, I've copied all the slot _a partitions to the slot _b ones, many of them in one operation, as contiguous blocks.

I began by

edl.exe /lprog_firehose_ddr.elf /qbc /v

when I entered edl mode in the phone.

Then,

edl.exe /u /qbc /v /g ,

which gave me this long reply, which includes the partition list:

Spoiler content hidden.

Unfortunately, when I add the /t option, to truncate the partitions, it rejects me with "Cannot determine active size of partition, no truncation possible", but that's not so important.

So, first, I've backed up all the LUNs, in case I needed to return to the original situation.

I could detail my operations, in case they be useful, if anyone asks me.

However, after copying all the _a to the _b slot partitions, my phone keeps on not booting. It just presents the shield splash screen, waits for some seconds and goes to black, like as powering off.

So, now, I plan to study better the version update process trying to do it in EDL mode in the hope that writing other partitions doesn't erase my userdata partition nor its encryption keys, which I still don't know where they are and I would thank anyone explaining us all.

I've found some strange or unexpected things:

1 The _a group in LUN4 has an intercalated "qmcs" partition, which I've had to skip, preventing me from copying completely in just one contiguous block.

2 I've compared the reported partition list with the partition list of the V705 stock rom taken from

https://rom.download.nubia.com/Europe/NX709J/V705/NX709J-update.zip

extracted with

https://github.com/crazystylus/otadump/releases/download/0.1.2/otadump-0.1.2-x86_64-pc-windows-msvc.zip

and there are a few differences:

4 8 mdtpsecapp_a 82438 1024 Inactive

4 9 mdtp_a 83462 8192 Inactive

are in the phone list, but not in the stock rom list, while

odm.img

product.img

system.img

system_ext.img

vendor.img

vendor_dlkm.img

are in the stock list and not in the phone list.

I wonder how the updating process handles them. I guess it would need some inteligent processing.

If anybody knowing more could explain, I'd be grateful.

Anyway, thanks a lot for your help and your app, dear Renate,

Juglar.