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Xiaomi Redmi Note 7 (xiaomi-lavender)

From postmarketOS Wiki
Revision as of 10:39, 15 January 2020 by Alexeymin (talk | contribs) (Add UART info)
This device is marked as not booting.
Status: Boots and has USB, but no more other functions
Xiaomi Redmi Note 7
Redmi Note 7
Redmi Note 7
Manufacturer Xiaomi
Name Redmi Note 7
Codename xiaomi-lavender
Released 2019
Hardware
Chipset Qualcomm SDM660 Snapdragon 660 (14 nm)
CPU 8-core (4x2.2 GHz Kryo 260 & 4x1.8 GHz Kryo 260)
GPU Adreno 512
Display 1080 x 2340
Storage 32 (64) Gb
Memory 3 (4) Gb
Architecture aarch64
Software
Original software Android 9, MIUI 10
postmarketOS
Category testing
Pre-built images no
postmarketOS kernel 4.4.153
Unixbench Whet/Dhry score -


Contributors

Maintainer(s)

Users owning this device


How to enter flash mode

Bootloader Unlocking

Like other Xiaomi devices, the user will have to acquire the bootloader unlock key: https://en.miui.com/unlock

The device will not unlock if the device isn't 7 days old (from the time when your device connects to internet and powered on, and linked with Mi Account)

Recovery mode

  • Turn the device off (or restart also works)
  • Hold volume+ button and power button
  • Once you feel vibration and phone turns on, release power button
  • Keep holding volume+ until you get to recovery.

Flashing (Download, Fastboot) mode

  • Same as recovery, but this time hold the volume- and power keys.

Installation

Flash a working custom Android ROM first

Flash a working custom Android ROM first - it will likely contain all needed custom partition images like vbmeta or dtbo (not sure if it's strictly needed). For example this [LineageOS 16.0 ROM]. The situation is a bit hard, because there is no official LineageOS release for this device yet, not even a official TWRP.

WIP

This is still a work-in-progress. If you want to test something, or help in the development, do:

  • make sure you have TWRP installed
  • backup boot and system partitions first from TWRP
  • checkout my development branch in pmaports (link below in links section)
  • zap & reinit pmbootstrap (pmbootstrap -y zap ; pmbootstrap init), choosing xiaomi-lavender as a device
  • then rebuild every package mentioned in the last commits on my branch (for now: pmbootstrap build --force --arch aarch64 linux-xiaomi-lavender device-xiaomi-lavender postmarketos-mkinitfs )
  • proceed with installation as usual (reboot device to fastboot mode, pmbootstrap install ; pmbootstrap flasher flash_kernel ; pmbootstrap flasher flash_rootfs).

Additional info

Partition list

Device Label Size in blocks Size in bytes Stock FS
mmcblk0p1 switch 8 8192
mmcblk0p2 dpo 8 8192
mmcblk0p3 fsc 8 8192
mmcblk0p4 limits 32 32768
mmcblk0p5 ssd 32 32768
mmcblk0p6 sec 20 20480
mmcblk0p7 vbmeta 64 65536
mmcblk0p8 vbmetabak 64 65536
mmcblk0p9 storsec 128 128K
mmcblk0p10 storsecbak 128 128K
mmcblk0p11 apdp 256 256K
mmcblk0p12 msadp 256 256K
mmcblk0p13 keystore 512 512K
mmcblk0p14 frp 512 512K
mmcblk0p15 rpm 512 512K
mmcblk0p16 rpmbak 512 512K
mmcblk0p17 hyp 512 512K
mmcblk0p18 hypbak 512 512K
mmcblk0p19 pmic 512 512K
mmcblk0p20 pmicbak 512 512K
mmcblk0p21 cmnlib 1024 1024K
mmcblk0p22 cmnlibbak 1024 1024K
mmcblk0p23 cmnlib64 1024 1024K
mmcblk0p24 cmnlib64bak 1024 1024K
mmcblk0p25 abl 1024 1024K
mmcblk0p26 ablbak 1024 1024K
mmcblk0p27 dip 1024 1024K
mmcblk0p28 ddr 1024 1024K
mmcblk0p29 toolsfv 1024 1024K
mmcblk0p30 devcfgbak 1024 1024K
mmcblk0p31 devcfg 1024 1024K
mmcblk0p32 tz 4096 4096K
mmcblk0p33 tzbak 4096 4096K
mmcblk0p34 mdtpsecapp 4096 4096K
mmcblk0p35 mdtpsecappbak 4096 4096K
mmcblk0p36 keymaster 1024 1024K
mmcblk0p37 keymasterbak 1024 1024K
mmcblk0p38 bluetooth 1024 1024K vfat
mmcblk0p39 lsti 2048 2048K
mmcblk0p40 xbl 3584 3584K
mmcblk0p41 xblbak 3584 3584K
mmcblk0p42 misc 4096 4096K
mmcblk0p43 devinfo 8192 8192K
mmcblk0p44 logfs 8192 8192K
mmcblk0p45 fsg 8192 8192K
mmcblk0p46 modemst1 8192 8192K
mmcblk0p47 modemst2 8192 8192K
mmcblk0p48 dsp 16384 16.0M vfat
mmcblk0p49 bk1 24576 24.0M
mmcblk0p50 mdtp 32768 32.0M
mmcblk0p51 bk2 16384 16.0M
mmcblk0p52 dtbo 8192 8192K
mmcblk0p53 dtbobak 8192 8192K
mmcblk0p54 splash 65536 64.0M
mmcblk0p55 persist 32768 32.0M ext4
mmcblk0p56 persistbak 32768 32.0M ext4
mmcblk0p57 logdump 65536 64.0M
mmcblk0p58 modem 196608 192M vfat
mmcblk0p59 rawdump 131072 128M
mmcblk0p60 boot 65536 64.0M
mmcblk0p61 recovery 65536 64.0M
mmcblk0p62 cache 262144 256M ext4
mmcblk0p63 system 3670016 3584M ext4
mmcblk0p64 vendor 2097152 2048M ext4
mmcblk0p65 cust 851968 832M ext4
mmcblk0p66 userdata 22802415 21.7G encrypted (dm-0)
mmcblk0rpmb 4096

Android Verified Boot (vbmeta)

This device is using Android Verified Boot ( https://android.googlesource.com/platform/external/avb/+/master/README.md ) so you may need to flash vbmeta partition with custom vbmeta.img from LineageOS zip or downloaded separately (from https://androidfilehost.com/?fid=1395089523397954291 for example). Or we need to find a way to generate it with avbtool and flash it during installation somehow. (add pmbootstrap flasher flash_vbmeta?)

DTBO partition

This device is using a dedicated partition to store the Device Tree Blob Overlay. Read more at https://source.android.com/devices/architecture/dto/partitions . We need to find a way to flash generated dt.img to dtbo partition during installation process. (add pmbootstrap flasher flash_dtbo?)

Update: looks like dtbo partition is not used during boot by LineageOS's kernel, because it is using appended DTB (CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE=y)

Update2: device tree from dtbo partition can still be used by bootloader?

Bootloader cmdline

Stock bootloader is doing nasty things with kernel command line: it passes a lot of arguments that make booting custom OS (like postmarketOS) impossible

Full list of stock command line parameters:

ramoops_memreserve=4M

rcupdate.rcu_expedited=1
console=ttyMSM0,115200,n8
androidboot.console=ttyMSM0
earlycon=msm_serial_dm,0xc170000
androidboot.hardware=qcom
user_debug=31
msm_rtb.filter=0x37
ehci-hcd.park=3
lpm_levels.sleep_disabled=1
sched_enable_hmp=1
sched_enable_power_aware=1
service_locator.enable=1
swiotlb=1
firmware_class.path=/vendor/firmware_mnt/image
loop.max_part=7
androidboot.selinux=permissive
buildvariant=eng

androidboot.verifiedbootstate=orange
androidboot.keymaster=1
root=PARTUUID=2a7f6d6d-1c23-febe-7efb-9ccfa1432ace
androidboot.bootdevice=c0c4000.sdhci
androidboot.serialno=ac1dde4e
androidboot.cpuid=0x39148c8c
androidboot.dp=0x0
androidboot.baseband=sdm
mdss_mdp.panel=1:dsi:0:qcom,mdss_dsi_nt36672a_tianma_fhdplus_video:config0:1:none:cfg:single_dsi
skip_initramfs
rootwait
ro
init=/init
androidboot.dtbo_idx=0
androidboot.fpsensor=fpc
androidboot.secureboot=1
androidboot.hwc=Global
androidboot.hwversion=1.29.0
androidboot.hwlevel=MP
androidboot.hwdevice=lavender

ramoops_memreserve=4M comes from defconfig, next from boot.img, others (starting with first androidboot. and below) come from bootloader directly.

Harmful kernel command line params from bootloader

Options like root=, skip_initramfs make kernel look for a specific partition to mount at /, skipping initramfs, which is incompatible with default booting methods of postmarketOS. That's why some tricky patches are needed, similar to ones used by Zhuowei in Google Pixel port: 1, 2.

Another hack to fix bootloader cmdline params by opendata26: init: ignore bootloader cmdline params for mounts

Some info on skip_initramfs kernel cmdline parameter: https://forum.xda-developers.com/apps/magisk/pixel-2-pixel-2-xl-support-t3697427/post74361728#post74361728

Way to get boot log

This device known to ship with the oem getlog fastboot command.

This is not a trivial command to use, but it is extremely useful as it allows side-stepping the need to boot in a known working system to use the ramoops console. The output of the command is a jumble, but is still usable for figuring out early boot issues. It is much better than having to rely on a booted system to get the information, but still not as good as having a dedicated serial access.

Example usage follows.


$ fastboot oem getlog 2>&1
(bootloader) [    0.000000] Booting Linux on physical CPU 0x0
[    0.000
(bootloader) 000] Initializing cgroup subsys cpuset
[    0.000000] Initi
(bootloader) alizing cgroup subsys cpu
[    0.000000] Initializing cgrou
(bootloader) p subsys cpuacct
[    0.000000] Initializing cgroup subsys
(bootloader) schedtune
[    0.000000] Linux version 4.4.153 (nixbld@loca
(bootloader) lhost) (gcc version 4.9.4 (GCC) ) #2 SMP PREEMPT Sat Nov 23
(bootloader)  20:31:33 UTC 2019
[    0.000000] Boot CPU: AArch64 Process
(bootloader) or [51af8014]
[...]


As the output of the command is on stderr, here's how to output to a file.


$ fastboot oem getlog > log.txt 2>&1


It is unknown if there are ways to make the output better. (Apply some kind error correction algorithm?)

EDIT: seems to not work for me, whatever you do, the output is:

$ fastboot oem getlog
                                                  (bootloader) [Macle]Maybe no last kmsg
OKAY [  0.000s]
Finished. Total time: 0.000s

Probably needs a crash? But I can read pstore-console (dmesg) logs from booted TWRP recovery fine..

Xiaomi Redmi Note 7 (lavender) UART test pins schematic

Getting logs through debug UART

You have to disassemble the phone (just removing back cover is enough). You'll have to heat up edges of the back cover (as shown in disassembling video, see Links below) before trying to remove it. Be careful! It is made of glass! Also be careful about fingerprint sensor connector, it is connected to a back cover you are trying to remove. Don't rip it.

In the center you will see 4 test points that are available. (See the picture) Two bigger ones (0.8mm) are EDL (FORCE_USB_BOOT) pins. UART test points are two smaller ones on the left (0.5mm). TP11 is UART TX (gpio 4), TP10 is UART RX (gpio 5). GND is that whole metal shielding, that covers the center of the board. So, to get debug logs from UART it is enough to connect UART TX from the board to RX pin on the converter, and connect GND between phone and GND pin on the converter.

Links