Boot fail with UBIFS_FS=y on Qualcomm msm8974/msm8226

[Brian Masney]

On Thu, Sep 22, 2022 at 05:55:51PM +0200, Luca Weiss wrote:
> sometime last year (June 2021?) I first noticed that with arm32 qcom_defconfig 
> under some circumstances I get weird boot failures on msm8974-fairphone-fp2, 
> and lately also seeing similar with apq8026-lg-lenok.
> 
> In short, with CONFIG_UBIFS_FS=y there's nothing from serial console, nothing 
> from earlycon, just nothing on serial at all. As soon as I disable this config 
> option and rebuild it boots up fine again.
> 
> At some point I also got this from fp2 logs, after I changed something in the 
> boot procedure (maybe fastboot boot instead of fastboot flash? I don't recall)
> 
> > Error: invalid dtb and unrecognized/unsupported machine ID
> >   r1=0x00000000, r2=0x00000000
> > Available machine support:
> > 
> > ID (hex)        NAME
> > ffffffff        Generic DT based system
> > 
> > Please check your kernel config and/or bootloader.
> 
> With CONFIG_UBIFS_FS=m and loading the module at runtime seems to work fine (at 
> least nothing visibly broke) although I didn't try mounting anything with that 
> file system.
> 
> Does anyone maybe have an idea what might cause this and/or how to debug this? 
> While just disabling UBIFS_FS in my config solves the issue I feel like this 
> should be resolved, because I also sometimes forget that I have to disable 
> this from qcom_defconfig and then wonder why my boards aren't booting.

Hey Luca,

I encountered a similar type of issue when I worked on the Nexus 5
phone. It's been awhile but from what I recall the issue was that the
generated Android boot image was too big, and it could cause the
"invalid dtb" error since the DTB is appended to the end of the kernel.
I have in my notes that I worked around the issue by enabling
CONFIG_MEDIA_SUPPORT_FILTER. Or you could just trying disabling
CONFIG_MEDIA_SUPPORT.

Brian