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WARNING: This Fastboot ROM applicable only if this specific circumstances are met; Phone just goes to blank screen right after splash screen (ASUS logo) appeared. Upon plugging it to computer, it mounts all partitions instead of just one unified partition like MTP mode does and Fastboot mode still accessible*. Slightly different situation as you currently facing on? Please refer to the following file, it might helps: androidfilehost.com/?fid=4279422670115730602
Cause of problem: Accidental reboot during configuration in parted especially msftdata flag not being set on system and userdata partiiton.
Just runs the flashall_AFT.cmd and fingers crossed your phone will be resurrected. Android upgrade or downgrade via recovery is applicable at this stage: asus.com/mobile/phones/all-series/zenfone-2-laser-ze550kl/helpdesk_bios
*You can just do one of this method that fits your situation:
1) Simultaneously hold down the Volume Up button and Power Button. Release it right after Fastboot mode appears on the screen.
2) If your Power Button broke (Like mine does) you just need to plug the phone in with simultaneously hold down the Volume Up button and you're good to go.
Nothing has been added/removed/modified and "-mfb=273 -md=1024m" parameters are used during recompression.
Original uploader's website can be found here: firmware27.com/2018/02/firmware-asus-zenfone-2-laser-ze550kl.html
(a) For additional download mirror purposes only. In the case of original download link or other mirrors no longer accessible.
(b) Not uploaded by the firmware27.com admin so I'm not affiliated with them. I'm not going to argue this my own property.