Linux cannot boot from BTRFS

[amstan]

It worked just fine earlier from ext4. Now my README.md is wrong.

I suspect something fishy with that EXFAT driver, https://old.reddit.com/r/fpgagaming/comments/i6btdw/question_how_to_boot_from_ext4_partition_on_sd/, maybe it's trying to do stuff out of the ordinary???

[    1.949064] mmc0: new high speed SDXC card at address aaaa
[    1.949702] Btrfs loaded, crc32c=crc32c-generic, zoned=no, fsverity=no
[    1.961668] mmcblk0: mmc0:aaaa SN128 119 GiB 
[    1.963118] Key type encrypted registered
[    1.974187]  mmcblk0: p1 p2 p3
[    1.982769] dma-pl330 ffe01000.pdma: Loaded driver for PL330 DMAC-341330
[    1.989502] dma-pl330 ffe01000.pdma:         DBUFF-512x8bytes Num_Chans-8 Num_Peri-32 Num_Events-8
[    2.012768] rtc-pcf8563 2-0051: pcf8563_write_block_data: err=-6 addr=0e, data=03
[    2.020254] rtc-pcf8563 2-0051: pcf8563_probe: write error
[    2.025749] rtc-pcf8563: probe of 2-0051 failed with error -5
[    2.045382] rtc-m41t80 2-0068: Can't clear HT bit
[    2.064134] i2c-gpio i2c_gpio: using lines 2012 (SDA) and 2013 (SCL)
[    2.070802] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[    2.081656] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[    2.088254] ALSA device list:
[    2.091225]   #0: Dummy 1
[    2.093994] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[    2.102614] cfg80211: failed to load regulatory.db
[    2.107413] dw-apb-uart ffc02000.serial0: forbid DMA for kernel console
[    2.116487] [EXFAT] trying to mount...
[    2.120684] VFS: Cannot open root device "mmcblk0p3" or unknown-block(179,3): error -5
[    2.128610] Please append a correct "root=" boot option; here are the available partitions:
[    2.136945] 0100            8192 ram0 
[    2.136955]  (driver?)
[    2.143059] 0101            8192 ram1 
[    2.143068]  (driver?)
[    2.149178] b300       124868608 mmcblk0 
[    2.149187]  driver: mmcblk
[    2.155980]   b301          512000 mmcblk0p1 c8010593-01
[    2.155989] 
[    2.162780]   b302            3072 mmcblk0p2 c8010593-02
[    2.162789] 
[    2.169579]   b303       124352512 mmcblk0p3 c8010593-03
[    2.169589] 
[    2.176385] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,3)

What a good boot looks like with ext4:

[    1.987288] mmc0: new high speed SDHC card at address aaaa
[    1.994060] mmcblk0: mmc0:aaaa SB32G 29.7 GiB 
[    2.003839] rtc-pcf8563 2-0051: pcf8563_write_block_data: err=-6 addr=0e, data=03
[    2.011366] rtc-pcf8563 2-0051: pcf8563_probe: write error
[    2.016874] rtc-pcf8563: probe of 2-0051 failed with error -5
[    2.030265]  mmcblk0: p1 p2 p3
[    2.038603] rtc-m41t80 2-0068: Can't clear HT bit
[    2.058421] i2c-gpio i2c_gpio: using lines 2012 (SDA) and 2013 (SCL)
[    2.065113] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[    2.076017] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[    2.082609] ALSA device list:
[    2.085585]   #0: Dummy 1
[    2.088359] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[    2.096978] cfg80211: failed to load regulatory.db
[    2.101776] dw-apb-uart ffc02000.serial0: forbid DMA for kernel console
[    2.120803] EXT4-fs (mmcblk0p3): mounted filesystem with ordered data mode. Opts: (null). Quota mode: disabled.
[    2.130946] VFS: Mounted root (ext4 filesystem) on device 179:3.
[    2.141263] devtmpfs: mounted
[    2.147458] Freeing unused kernel image (initmem) memory: 1024K
[    2.153767] Run /sbin/init as init process
[    2.157863]   with arguments:
[    2.160829]     /sbin/init
[    2.163536]   with environment:
[    2.166673]     HOME=/
[    2.169034]     TERM=linux
[    2.171739]     memmap=513M$511M
[    2.342001] random: fast init done
[    2.756380] systemd[1]: System time before build time, advancing clock.
[    2.794455] systemd[1]: Failed to find module 'autofs4'
[    2.830397] systemd[1]: systemd 250.3-3-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 -PWQUALITY +P11KIT -QRENCODE +BZIP2 +LZ4 +XZ +ZLIB +ZSTD -BPF_FRAMEWORK +XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified)
[    2.862688] systemd[1]: Detected architecture arm.

[amstan]

[    2.223111] VFS: Mounted root (btrfs filesystem) on device 0:13.