[General Questions and Answers] himister:
Or you can just leave the stock recovery and when in need for backup, just boot the CWM. I made myself a few backups on the go just by booting. It's kinda same. Operates in ramdisk just doesn't stay when rebooted and you can wipe the data and cache from stock....

which oddly does something different...last night I wiped from stock the phone which is still on B183, just system partition is flashed to B515, cause it works very well and easy rooted with SuperSU. But the thing is, when wiped from stock recovery, the cust settings and theme reverted to basic huawei y530, no themes and I was looking for that. Cust still loads under /data/cust but doesn't initialise the themes or bootlogo. Still can't work out what is responsible for turning on/off the theme engine.

On the subject of Downgrade

For some time, I've been investigating the possibility and it's a pretty tough one.

Making the UPDATE.APP by repacking from Huawei update extractor would be very risky, as some of us know and understand the digitally signed files and (still unknown) partitions map of the device. I remember back in the day, when I had G300 someone made a downgrade from a installable cwm zip. The updater-script has been made to rewrite oem and modem partitions with a previous versions so when stock update is performed as downgrade, it worked cause of different signed versions inside oemsbl files in our case.

Here is the example of old G300 dowgrade update-script:

ui_print(" ");
ui_print("Downgrade to B895");
ui_print(" ");

ui_print("Installing...");
package_extract_file("files/amssmbn.img", "/dev/block/mmcblk0p3");
package_extract_file("files/modem_st1.mbn", "/dev/block/mmcblk0p10");
package_extract_file("files/modem_st2.mbn", "/dev/block/mmcblk0p11");
package_extract_file("files/qcsbl.img", "/dev/block/mmcblk0p9");
package_extract_file("files/oemsbl.img", "/dev/block/mmcblk0p14");
package_extract_file("files/recovery.img", "/dev/block/mmcblk0p16");
ui_print("Installation finished");

Some of us tried to apply downgrade or even perform stock reflash with stock update.app but after flashing higher versions it always ended with and error in check oemsbl ver list.

So, when we extract the update app with a huawei update extractor there are two files which are flashed along with other partitions:

OEMSBL_VER.img

contains the current firmware version

Y530-U00V100R001C900B515_BOOT

and, which contains all the previous versions that can be updated:

OEMSBL_VERLIST.img

Y530-U00V100R001C00B166_BOOT
Y530-U00V100R001C00B170_BOOT
Y530-U00V100R001C00B171_BOOT
Y530-U00V100R001C00B175_BOOT
Y530-U00V100R001C00B179_BOOT
Y530-U00V100R001C00B180_BOOT
Y530-U00V100R001C00B181_BOOT
Y530-U00V100R001C900B185_BOOT
Y530-U00V100R001C900B186_BOOT
Y530-U00V100R001C900B188_BOOT
Y530-U00V100R001C900B189_BOOT
Y530-U00V100R001C900B190_BOOT
Y530-U00V100R001C900B191_BOOT
Y530-U00V100R001C900B192_BOOT
Y530-U00V100R001C900B193_BOOT
Y530-U00V100R001C900B194_BOOT
Y530-U00V100R001C900B195_BOOT
Y530-U00V100R001C900B196_BOOT
Y530-U00V100R001C900B501_BOOT
Y530-U00V100R001C900B502_BOOT
Y530-U00V100R001C900B503_BOOT
Y530-U00V100R001C900B504_BOOT
Y530-U00V100R001C900B505_BOOT
Y530-U00V100R001C900B506_BOOT
Y530-U00V100R001C900B507_BOOT
Y530-U00V100R001C900B508_BOOT
Y530-U00V100R001C900B509_BOOT
Y530-U00V100R001C900B510_BOOT
Y530-U00V100R001C900B511_BOOT
Y530-U00V100R001C900B512_BOOT
Y530-U00V100R001C900B513_BOOT
Y530-U00V100R001C900B514_BOOT
Y530-U00V100R001C900B515_BOOT
G730-C10V100R001C92B130_BOOT

I think that now, idea is pretty much obvious but still there's a risk.

Making the cwm install-update-downgrade zip is not a problem.

But question stays, will it work in our case?

If anyone has any further info or idea how this could be done pls do comment.