Rock64 panic "dwmmc_ring_setup: error != 0 (27)" is repeatable on my main-n247756-348c41d1815d based build

# dd if=lx2160acex7_2000_700_2900_8_5_2-bc46e34.img of=/dev/mmcsd0 bs=1m conv=sync
panic: dwmmc_ring_setup: error != 0 (27)

cpuid = 3
time = 1626039590
KDB: stack backtrace:
db_trace_self() at db_trace_self
db_trace_self_wrapper() at db_trace_self_wrapper+0x30
vpanic() at vpanic+0x188
panic() at panic+0x44
dwmmc_ring_setup() at dwmmc_ring_setup+0x144
bus_dmamap_load() at bus_dmamap_load+0xf8
dwmmc_next_operation() at dwmmc_next_operation+0x284
dwmmc_request() at dwmmc_request+0x130
mmc_wait_for_request() at mmc_wait_for_request+0x12c
mmcsd_rw() at mmcsd_rw+0x1b0
mmcsd_task() at mmcsd_task+0x2b0
fork_exit() at fork_exit+0x94
fork_trampoline() at fork_trampoline+0x14
KDB: enter: panic
[ thread pid 19 tid 100086 ]
Stopped at      kdb_enter+0x48: undefined       f904011f
db> 


Using bs=4k value had no such problem:

# dd if=lx2160acex7_2000_700_2900_8_5_2-bc46e34.img of=/dev/mmcsd0 bs=4k conv=sync
134912+0 records in
134912+0 records out
552599552 bytes transferred in 220.193416 secs (2509610 bytes/sec)

I did not try other figures.

For reference:

# uname -apKU
FreeBSD Rock64_RPi_4_3_2v1p2 14.0-CURRENT FreeBSD 14.0-CURRENT #4 main-n247756-348c41d1815d-dirty: Mon Jul  5 10:28:25 PDT 2021     root@CA72_16Gp_ZFS:/usr/obj/BUILDs/main-CA53-nodbg-clang/usr/main-src/arm64.aarch64/sys/GENERIC-NODBG-CA53  arm64 aarch64 1400025 1400025

===
Mark Millard
marklmi at yahoo.com
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away in early 2018-Mar)