I noticed that with raspberrypi4 (model B) a reboot with : reboot '0 tryboot' is sometimes not reached to the firmware:
[ 1682.575578] reboot: Restarting system with command '0 tryboot 0.79 Boot watchdog init. max duration 180s part 0 started_at 788969 end_at 180788969
0.79 RPi: BOOTSYS release VERSION:9cd61c53 DATE: 2026/04/14 TIME: 22:17:01
0.80 BOOTMODE: 0x06 partition 0 build-ts BUILD_TIMESTAMP=1776201421 serial 4b74e4a2 boardrev a03115 stc 806326
0.81 PM_RSTS 00001020
0.81 POWER_OFF_ON_HALT: 0 WAIT_FOR_POWER_BUTTON 0 power-on-reset 0
0.82 EEPROM ID 0xef3013
0.82 SFDP None
0.83 Boot watchdog init. max duration 180s part 0 started_at 788969 end_at 180788969
0.84 part 00000000 reset_info 00000000
0.84 uSD voltage 3.3V
0.85 init_sdram_1350
0.88 Initialising SDRAM rank 1 total-size: 8Gbit 0 part: 0 (0x07 0x00)
0.89 memsys_init: 0 8Gbit MCB 0x80015ff0: 9576
0.89 DDR 3200 Mbps dual-rank:0 byte-mode:0 size-gbit:8 part-config:0
1.67 SD_SB 11003110
1.84 OTP boardrev a03115 bootrom 8b0 8b0
1.84 Customer key hash 0000000000000000000000000000000000000000000000000000000000000000
1.84 VC-JTAG unlocked
2.14 RPi: BOOTLOADER release VERSION:9cd61c53 DATE: 2026/04/14 TIME: 22:17:01
2.16 BOOTMODE: 0x06 partition 0 build-ts BUILD_TIMESTAMP=1776201421 serial 4b74e4a2 boardrev a03115 stc 2167240
2.17 EEPROM ID 0xef3013
2.17 SFDP None
2.24 SD_OC: 0
2.46 Boot mode: SD (01) order f4
2.26 SD HOST: 200000000 CTL0: 0x00800000 BUS: 400000 Hz actual: 390625 HZ div: 512 (256) status: 0x1fff0000 delay: 276
2.27 SD HOST: 200000000 CTL0: 0x00800f00 BUS: 400000 Hz actual: 390625 HZ div: 512 (256) status: 0x1fff0000 delay: 276
2.54 OCR c0ff8000 [334]
CID: 00035344534432353685c6c29ed5018c
CSD: 400e00325b590007725f7f800a404000
2.55 SD: bus-width: 4 spec: 2 SCR: 0x02458043 0x00000000
2.56 SD HOST: 200000000 CTL0: 0x00800f04 BUS: 50000000 Hz actual: 50000000 HZ div: 4 (2) status: 0x1fff0000 delay: 2
2.57 MBR: 0x00000001,16785441 type: 0xee
2.57 MBR: 0x00000000, 0 type: 0x00
2.58 MBR: 0x00000000, 0 type: 0x00
2.58 MBR: 0x00000000, 0 type: 0x00
2.88 Trying partition: 0
2.59 GPT 0000000000000000000000004d9b9ef0 000000001 001002021 num-partitions 128 entry-size 128 pentry 2 first 0
2.60 GPT partition: 0 ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 000002000..000101fff
2.60 Matched GUID bootable-part-idx 0 want partition 0
2.13 type: 32 lba: 8192 'mkfs.fat' ' boot ' clusters 130812 (8)
2.61 rsc 32 fat-sectors 1024 root dir cluster 2 sectors 0 entries 0
2.62 FAT32 clusters 130812
2.31 Read autoboot.txt bytes 65 hnd 0x25f
2.63 Select partition rsts 0 C(boot_partition) 2 EEPROM config 0 result 2
2.39 Trying partition: 2
2.64 GPT 0000000000000000000000004d9b9ef0 000000001 001002021 num-partitions 128 entry-size 128 pentry 2 first 0
2.65 GPT partition: 0 ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 000002000..000101fff
2.65 Matched GUID bootable-part-idx 0 want partition 1
2.66 GPT partition: 1 ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 000102000..000201fff
2.67 Matched GUID bootable-part-idx 1 want partition 1
2.77 type: 32 lba: 1056768 'mkfs.fat' ' boot ' clusters 130812 (8)
2.68 rsc 32 fat-sectors 1024 root dir cluster 2 sectors 0 entries 0
2.68 FAT32 clusters 130812
2.91 secure-boot
2.93 Loading boot.img ...
2.69 boot.sig
2.69 hash: 547de1ad0c5ade7ff13812d137825a0c390aa7e2f583c8627b06794f929b7475
2.70 ts: 1302044400
2.70 rsa2048: 55c98a1173caf82bd0ad6d9410de2242c830f28101760e0b0934281b0ce014ab2c83ea81760047f7644f7e766124993563bfb9c9696a94c01b13f235bb50adb75f3bfeec424e37bc69bea561f97f6676724bc42774a2b272c1eafeaf05bdbf5130edae92047316af1553018818a72ff0f97745da5995158
d269317cc1b82d2e5030f778c917b55695b87c203eb01df5d959fb19346dd0982913cd72f9542f08b1da25e340dc99f12385372f81b0ca57aecbe612b28c25a544a0d09260b00dc585b9323f21db82a7f00a1681362fffda423af7858eee5f2e54b7e72ed4c1c4ccc74a662c021b87335c1fff05d1a6dc7c80844ba4f90ec56
e51379694367ccfefd
6.97 Verifying
14.86 RSA verify
14.81 rsa-verify pass (0x0)
15.05 MBR: 0x00000000, 0 type: 0x00
15.05 MBR: 0x00000000, 0 type: 0x00
15.05 MBR: 0x00000000, 0 type: 0x00
15.05 MBR: 0x00000000, 0 type: 0x00
15.63 Trying partition: 0
15.65 type: 32 lba: 0 'mkfs.fat' ' rpi4-64 ' clusters 149188 (1)
15.07 rsc 32 fat-sectors 1166 root dir cluster 2 sectors 0 entries 0
15.07 FAT32 clusters 149188
15.13 Read config.txt bytes 2848 hnd 0x223
15.11 [ramdisk] pieeprom.upd not found
15.11 [ramdisk] recover4.elf not found
15.12 [ramdisk] recovery.elf not found
15.50 Read start4.elf bytes 2305632 hnd 0x17c2e
15.52 Read fixup4.dat bytes 5499 hnd 0x238
15.56 0x00a03115 0x00000000 0x00003fff
15.60 MEM GPU: 76 ARM: 948 TOTAL: 1024
15.66 Firmware: 288930ab4712b99596f32732664aaaeb881ef1e0 May 21 2026 11:20:25
15.02 Starting start4.elf @ 0xfec00200 partition 0
15.34 PCI0 reset
15.43 +
MESS:00:00:15.561484:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:15.565359:0: board: boardrev a03115 otp a03115
MESS:00:00:15.569142:0: brfs: File read: 2848 bytes
MESS:00:00:15.595538:0: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:15.600046:0: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:15.617205:0: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:15.621707:0: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:15.627193:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:16.640831:0: Boot watchdog running
MESS:00:00:17.125341:0: gpioman: gpioman_get_pin_num: pin DISPLAY_DSI_PORT not defined
MESS:00:00:17.432388:0: *** Restart logging
MESS:00:00:17.433464:0: brfs: File read: 2848 bytes
MESS:00:00:17.443641:0: hdmi: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:17.448671:0: hdmi: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:17.459294:0: hdmi: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:17.464315:0: hdmi: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:17.469913:0: hdmi: HDMI:hdmi_get_state is deprecated, use hdmi_get_display_state instead
MESS:00:00:17.483706:0: hdmi: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:17.488729:0: hdmi: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:17.499351:0: hdmi: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:17.504378:0: hdmi: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:17.509976:0: hdmi: HDMI:hdmi_get_state is deprecated, use hdmi_get_display_state instead
MESS:00:00:17.518742:0: HDMI0: hdmi_pixel_freq_limit: 300000000
MESS:00:00:17.524383:0: HDMI1: hdmi_pixel_freq_limit: 300000000
MESS:00:00:17.540818:0: dtb_file 'bcm2711-rpi-4-b.dtb'
MESS:00:00:17.543446:0: brfs: File read: /mfs/sd/bcm2711-rpi-4-b.dtb
MESS:00:00:17.548927:0: Loaded 'bcm2711-rpi-4-b.dtb' to 0x100 size 0xdc57
MESS:00:00:17.570932:0: brfs: File read: 56407 bytes
MESS:00:00:17.573185:0: brfs: File read: /mfs/sd/overlays/overlay_map.dtb
MESS:00:00:17.608959:0: brfs: File read: 5971 bytes
MESS:00:00:17.610870:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:17.617006:0: dtparam: spi=on
MESS:00:00:17.627841:0: dtparam: i2c1=on
MESS:00:00:17.637518:0: dtparam: i2c_arm=on
MESS:00:00:17.647445:0: dtparam: watchdog=on
MESS:00:00:17.659210:0: brfs: File read: 2848 bytes
MESS:00:00:17.661489:0: brfs: File read: /mfs/sd/overlays/tpm-slb9670.dtbo
MESS:00:00:17.675608:0: Loaded overlay 'tpm-slb9670'
MESS:00:00:17.724814:0: brfs: File read: 779 bytes
MESS:00:00:17.727383:0: brfs: File read: /mfs/sd/overlays/rpi-ft5406.dtbo
MESS:00:00:17.733817:0: Loaded overlay 'rpi-ft5406'
MESS:00:00:17.744348:0: brfs: File read: 842 bytes
MESS:00:00:17.746726:0: brfs: File read: /mfs/sd/overlays/rpi-backlight.dtbo
MESS:00:00:17.759360:0: Loaded overlay 'rpi-backlight'
MESS:00:00:17.772363:0: brfs: File read: 489 bytes
MESS:00:00:17.774142:0: brfs: File read: /mfs/sd/cmdline.txt
MESS:00:00:17.779466:0: Read command line from file 'cmdline.txt':
MESS:00:00:17.785325:0: 'dwc_otg.lpm_enable=0 console=serial0,115200 ro net.ifnames=0 vt.global_cursor_default=0 consoleblank=0 loglevel=7 ima_appraise=log evm=fix security=selinux enforcing=0 trusted.source=rpifwcrypto verity_mode=ignore'
MESS:00:00:17.930752:0: Enabling early watchdog
MESS:00:00:17.933078:0: brfs: File read: 215 bytes
MESS:00:00:18.333365:0: brfs: File read: /mfs/sd/kernel8.img
MESS:00:00:18.335921:0: Loaded 'kernel8.img' to 0x200000 size 0x2c25a00
MESS:00:00:18.342272:0: Device tree loaded to 0x2eff1b00 (size 0xe40b)
MESS:00:00:18.351150:0: uart: Set PL011 baud rate to 103448.300000 Hz
MESS:00:00:18.357580:0: uart: Baud rate change done...
MESS:00:00:18.359597:0:[ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd083]
[ 0.000000] Linux version 6.18.33-v8 (oe-user@oe-host) (aarch64-oe-linux-gcc (GCC) 15.3.0, GNU ld (GNU Binutils) 2.46.1) #1 SMP PREEMPT Thu May 28 02:31:14 UTC 2026
[ 0.000000] KASLR enabled
[ 0.000000] random: crng init done
[ 0.000000] Machine model: Raspberry Pi 4 Model B Rev 1.5
[ 0.000000] efi: UEFI not found.
[ 0.000000] Reserved memory: created CMA memory pool at 0x000000002ac00000, size 64 MiB
[ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
[ 0.000000] OF: reserved mem: 0x000000002ac00000..0x000000002ebfffff (65536 KiB) map reusable linux,cma
[ 0.000000] OF: reserved mem: 0x000000003ef74c60..0x000000003ef74df5 (0 KiB) nomap non-reusable nvram@0
[ 0.000000] OF: reserved mem: 0x000000003ef74b20..0x000000003ef74c27 (0 KiB) nomap non-reusable nvram@1
[ 0.000000] NUMA: Faking a node at [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] Faking node 0 at [mem 0x0000000000000000-0x000000003b3fffff] (948MB)
[ 0.000000] NODE_DATA(0) allocated [mem 0x3b1de280-0x3b1e0fff]
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000003b3fffff]
[ 0.000000] On node 0, zone DMA: 19456 pages in unavailable ranges
[ 0.000000] percpu: Embedded 33 pages/cpu s96152 r8192 d30824 u135168
[ 0.000000] Detected PIPT I-cache on CPU0
[ 0.000000] CPU features: detected: Spectre-v2
[ 0.000000] CPU features: detected: Spectre-v3a
[ 0.000000] CPU features: detected: Spectre-v4
the TRYBOOT flag is missing in this one, this is happening only from time to time.
I noticed that with raspberrypi4 (model B) a reboot with : reboot '0 tryboot' is sometimes not reached to the firmware:
the TRYBOOT flag is missing in this one, this is happening only from time to time.