[Android Q&A, Help & Troubleshooting] DMaglaras:
Test Results: CM-11, FIUIv2.xx.0, and MIUIv7.x by hb72k and dabi01

[MENTION=6800235]dabi01[/MENTION]

[MENTION=6836126]HB72K[/MENTION]

@y550 dev team

In the past 20 days (June 6-26, 2016) I flashed (per TWRP-3.0.2.0) & tested several CM-11 based ROMs dated 2016, and published mainly by dabi01 and hb72k. I prefer CM-11 to 12.1/13.0 because it is more easily customizable pre-flash, more stable. More importantly, 12.1/13.0 based ROMs are not yet testified for everyday use.

Before flashing any of these ROMs I (a) debloated it aggressively; (b) customized apps aggressively, getting rid of some and replacing many with better third party alternatives; (c) extracted then deleted libs the way DeltaGapps/OpenGapps do; (d) modified authors' tweaks, especially those pertaining to ZRAM (disabled), swap files (just a single 175MB large one in /cache), hosts (used the big one from MoaAB), and gps.conf (substituted one recommended for my country for the defaults). (e) Tweaks pertaining to cpu (governors) and battery I left unchanged. My debloating mania may or may not have resulted in breaking some UI elements, so wherever I heretoafter report a function as broken there is a probability that I am the culprit. My modified tweaks were, on the other hand, very well received by the ROMs; I daresay they even performed better.

I tested the ROMs only for stability, speed, and functionality for (a) making and receiving calls and (b) using as a PDA. No games; after all, this is a 1GB RAM/4GB NAND device.

These are my test results:

1. CM-11-20160329-UNOFFICIAL-y550.

Compiled by hb72k. Security patch level=20160301.

Impressive in every regard, except that it did not recognize the same SIM which worked in every other phone and under every other ROM. If that is fixed, and the ROM is recompiled to include the latest (at this writing, 20160601) security patches, it would be my first choice.

(Subsequent attempts to flash fresher versions of CM-11 based ROMs with security patch level=20160301 (e.g., Y-UNOFFICIAL-y550) failed with TWRP Error Code 7.)

2. FIUI (v2.32.0) by dabi01 -Antutu record-breaker ROM.

Ported from a ROM for Redmi with build date:20150620.

Impressive. FIUI is a CM-11 with a leaner, faster and more polished chinese interface. I used it for a good 15 days, made extensive usability & functionality notes about core OS, UI and apps, and I reverted to it after every other ROM disappointed me (see below). It has three problems, the last of which may be a deal breaker:

(1) [Mere nuisances] In simplifying the interface, the Chinese developers cut too deep into CM-11's flesh. Some functionality has been taken away, a few customizations are inferior to those replaced, some built-in apps have been massacred for no good reason (replacing them with CM-11 or PAC-man or SlimKat equivalents solves it). Some menus have not been translated from the Chinese original: FIUI is not 100%-ly internationalized.​

(2) [Almost a deal breaker] Initially I could not believe it, but after 15 days of testing I could not deny it. FIUI has amputated the contacts apk -- the functionality has been halved (no filtering, no search), and this half has been subsumed into the telephony (dialer) apk. It is not tragic, because you can regain this functionality using an alternative contacts/dialer app. (My favorite is ExDialer. I also tested Contacts+, and it too worked.)​

(3) [Deal breaker] When using the telephony app (either make or answer a call), sound volume output through the microphone/loudspeaker is so low as to be almost silent. Sound volume output through 3.5mm earsets or BT earsets is better, but not good. No such problem exists when using the FM Radio app or a music or audio book player app. Replacing DSPManager with Viper4Android 2.4.0.1 had no effect. My conclusion: either dabi01 broke the telephony app in porting it, or it was already broken in FIUI itself. It goes without saying that a ROM which silences calls may be OK for a tablet, but for a phone it is a deal breaker.
​

3. MIUI v7.5.xx by dabi01 pre-final.

Security patch level: 20151201.

Three words: excellent but tricky. I can understand why everyone who has come in touch with it praises it: compared to CM-11 from which it obviously derives it is like rich man's ROM to poor man's ROM. Excellent on every score: system, storage, usability. But also tricky. In my debloating mania and out of sheer habit, I had replaced the default launcher with Nova. Everybody does it with every ROM, right? Well, not this ROM. Turns out that the launcher incorporates additional functionality whose absence breaks the system, at least the UI. And without UI, you are left with something like a Linux with a broken console and no ALT-F2 to a fresh console. Trying to re-flash the missing pieces not only broke the ROM for good but also soft-bricked the phone. According to dabi01 in another post, MIUI v7 habitually soft-bricks phones unless you upgraded from MIUI v6. VERDICT: A great ROM, shall definitely give it a fresh try, but unless it can be made as easy to cut and recut as CM-11 and FIUI not for me, at least not my #1 choice.

4. FIUI (v2.26) by dabi01 - "bugless".

Ported from a ROM for Redmi with build date:20150620.

I tried this "bugless" ROM because I liked FIUI except for its low telephony volume bug and hoped this ROM fixed it. Bugless? Could not recognize WiFi (no WiFi MAC address, auto-configured for a nonroutable Class A IP address -- my network is nonroutable Class C /27). Cellular network was recognized. I gave this ROM a second try this time leaving it as posted by dabi01 (no debloating, no customization) and WiFi continued to be dead. dabi01, did you forget to incorporate the MAC address fix?

5. Further tests (Plan).

Ideal ROM is CM-11 freshly compiled for the y550 so that the latest security patches are incorporated. FIUI is not up to date security wise (at least so it looks), and at any rate it is not ready for everyday use until its sound bug is fixed; should these two provisos disappear, though, it is first choice. MIUI is probably on a par with CM-11, however for guys like me who love cutting and recutting their ROM it is not a safe choice.

Re-try to flash CM-11/Y after wiping phone clean and using a fresh SD card.

Re-try MIUI after wiping phone clean and using a fresh SD card for its superior experience.

Thanks & congratulations to dabi01, hb72k and the whole dev team.