[Xiaomi Mi 8 Questions & Answers] BobHop:
Hi everyone,

I was recently given a Xiaomi Mi 8 which is now blocked in a boot loop, because Xiaomi apparently thought it was good engineering to give people tools that make flashing easy, but are rigged with a deadly "clean all and lock" option ON BY DEFAULT. Please allow me to sum things up.

HISTORY:

My mom had a Xiaomi Mi 8, bought a newer phone for some reason.

She had a reseller fix/clean the Mi 8 and gave it to me as a present; all in excellent shape.

My wife's phone sucked more than mine, so I migrated her number/data/etc to the Mi 8 for her to use.

Everything seemed fine, I let the system update to MIUI 12 (don't know which one was installed before).

Only then did we notice: no sound coming out from the ear speaker... Dunno if it worked before MIUI 12. My mom never had a problem with it before.

After looking it up online, I saw sometimes system updates did screw up parts of the phone for no reason.

I downloaded Mi Flash Tool + global MIUI 11 rom, hoping to downgrade and see if it fixes the ear speaker.

Bootloader was already unlocked, downgrading is apparently officially authorized, so... I flashed the phone!

After installing and rebooting, it got stuck in "This MIUI version can't be installed on this device".

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TECHNICAL:

Phone: Xiaomi Mi 8, second hand, no idea what the original region was.

OS: MIUI 11, downgraded from MIUI 12.

ROM: dipper_global_images_V11.0.5.0.QEAMIXM_20200706.0000.00_10.0_global

Bootloader: previously unlocked, now locked because Mi Flash Tool was set on "clean all and lock" and I didn't know better.

Connections: USB OK, fastboot/sideload OK, EDL OK

Mi account: didn't have one, I do now, couldn't link it to the phone though.

After lots of research, tests, hopes and disillusionments, I'm still stuck and can't flash anything into it, can't recover anything, can't move on. I did many attempts in EDL mode (opening the phone allowed me to notice it had been opened before, I guess by the repair shop my mom took it to). I'm appalled that Xiaomi let people flash their phone with official tools so easily, yet fail to warn us VISIBLY that 1) your phone may be from a different region without you knowing it; 2) you aren't allowed to flash a Global rom on a China rom; 3) the default option in Mi Flash Tool is to lock your bootloader after flashing, which is THE reason why your phone may end up locked by mistake.

I got my hand on various versions of Mi Flash Tool (latest, 2018, beta), Mi Flash Unlock (early, recent), Qualcomm drivers, Miracle Box Thunder Edition 2.82, XiaomiToolV2, and of course Minimal ADB & Fastboot. EDL is a no-brainer now, plugging the battery out/in, pressing VOL- and Power too... I tried to flash a Chinese Developer Fastboot rom, I tried firehose patchs, nothing ever worked. Apparently I'm now out of luck, being stuck in a bootloop with a MIUI version that wasn't meant for my phone, with a bootloader that's been locked again, without a linked account to unlock it. And no, I don't wanna drive to a Xiaomi shop, I don't wanna pay a stranger to unlock my account with Teamviewer – basically my mom gave us that MI 8 so that we would not have to pay anything. Otherwise I would've paid to replace the battery of my wife's Samsung A5 2016 and we would've been fine.

Could anyone knowledgeable enough tell me if there's another way to fix that phone, or if it's definitely stuck and I should sell it for parts? Thanks for reading.