EMUI leftover apps, how to remove them?

[iwtfmcl]

Having read so many praises about Huawei's EMUI (Emotion UI) I decided just to try it on my Ascend P1.
I thought it was like completely new ROM but it's just a launcher that, I believe tried to borrow from MIUI, and it's a joke. Nothing beats MIUI!
So I went back to MIUI and to my suprise I found Facebook and Twitter apps still there. They are stuck in data/cust/app folder and I can't uninstall them or remove them in any way. Not with root explorer nor with any root uninstaller. I confirmed that I am rooted because I can delete files in other system folders and uninstall other system apps.
So, two questions:
1. Doesn't system partition get wiped when I fresh install MIUI?
2. Anyone can tell me how to remove those two apps?

Thanks in advance.

 

[iwtfmcl]

Having read so many praises about Huawei's EMUI (Emotion UI) I decided just to try it on my Ascend P1.
I thought it was like completely new ROM but it's just a launcher that, I believe tried to borrow from MIUI, and it's a joke. Nothing beats MIUI!
So I went back to MIUI and to my suprise I found Facebook and Twitter apps still there. They are stuck in data/cust/app folder and I can't uninstall them or remove them in any way. Not with root explorer nor with any root uninstaller. I confirmed that I am rooted because I can delete files in other system folders and uninstall other system apps.
So, two questions:
1. Doesn't system partition get wiped when I fresh install MIUI?
2. Anyone can tell me how to remove those two apps?

Thanks in advance.

I got the answer for question #2. Using ES File Explorer I discovered that /cust is mounted as RO. Changing it to RW I was able to delete those apps. I also learned of existence of cust.img or cust.bin in Huawei ROMs. So I deleted all this crap.

Question #1 is what still puzzles me. How come that when you flash MIUI fresh there are remains of the previous ROM on the device??? Doesn't flashing new ROM, like MIUI do away with everything from previous ROM?

 

[kurgan]

You must format cust

 

[Acid]

Depends if you did full wipe before flashing MIUI? Apps are on /data partition so its nothing new that flashing MIUI without wipe will leave those apps. MIUI formats only /system partition.