Hi there,
I have an Asus Flip C302 (HWID CAVE) on which I had previously run successfully older versions of Debian and Ubuntu under RW_LEGACY bios.
More recently, I have removed the write-protect screw and have flashed MrChromebox UEFI Full ROM, without a problem. Now both Debian 13 and Ubuntu 25.04 install OK, at least apparently, and they also boot OK but… after about five minutes, the mmc disk starts triggering kernel error messages (mmc_select_hs400 failed, error -84; mmc_hs400_to_hs200 failed, error -110) until it gets remounted read-only, locking up the system. See the details below.
I guess the prime suspect is the kernel’s mmc system – it’s definitely something to do about the “auto-tuning” that this module is trying to do with the speed modes HS400/HS200, but I have no more clues. Moreover, mmc doesn’t seem to expose any tuning knobs as kernel options to try. On the other hand, I’d like to ask you guys if you think that this could be an issue caused by the UEFI ROM instead.
Cheers,
JL
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MrChromebox-2512.1 (Release Date: 01/15/2026)
root@asuscb:~# dmesg | grep mmc
[ 1.156228] mmc1: SDHCI controller on PCI [0000:00:1e.4] using ADMA 64-bit
[ 1.156346] mmc0: SDHCI controller on PCI [0000:00:1e.6] using ADMA 64-bit
[ 1.593908] mmc1: new HS400 MMC card at address 0001
[ 1.607654] mmcblk1: mmc1:0001 DF4064 58.2 GiB
[ 1.612711] mmcblk1: p1 p2
[ 1.613338] mmcblk1boot0: mmc1:0001 DF4064 4.00 MiB
[ 1.614503] mmcblk1boot1: mmc1:0001 DF4064 4.00 MiB
[ 1.615787] mmcblk1rpmb: mmc1:0001 DF4064 4.00 MiB, chardev (241:0)
[ 4.609102] EXT4-fs (mmcblk1p2): orphan cleanup on readonly fs
[ 4.611200] EXT4-fs (mmcblk1p2): mounted filesystem dbd5f723-3ff7-4e47-8d2d-391996054fa4 ro with ordered data mode. Quota mode: none.
[ 5.892525] EXT4-fs (mmcblk1p2): re-mounted dbd5f723-3ff7-4e47-8d2d-391996054fa4 r/w.
[ 279.079942] mmc1: mmc_select_hs400 failed, error -84
[ 329.436705] mmc1: mmc_hs400_to_hs200 failed, error -110
[ 403.774464] mmc1: mmc_hs400_to_hs200 failed, error -110
[ 648.374145] mmc1: mmc_select_hs400 failed, error -84
[ 802.281871] mmc1: mmc_hs400_to_hs200 failed, error -110
[ 1104.366041] mmc1: mmc_select_hs400 failed, error -84
[ 1127.211176] mmc1: mmc_select_hs400 failed, error -84
[ 1219.280758] mmc1: mmc_select_hs400 failed, error -84
[ 1693.440143] mmc1: cache flush error -110
[ 1693.440183] I/O error, dev mmcblk1, sector 61571672 op 0x1:(WRITE) flags 0x29800 phys_seg 1 prio class 2
[ 1693.440218] Aborting journal on device mmcblk1p2-8.
[ 1693.440932] EXT4-fs error (device mmcblk1p2): ext4_journal_check_start:84: comm rs:main Q:Reg: Detected aborted journal
[ 1693.440975] EXT4-fs error (device mmcblk1p2): ext4_journal_check_start:84: comm systemd-journal: Detected aborted journal
[ 1693.450897] EXT4-fs (mmcblk1p2): Remounting filesystem read-only
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