Carrot

High ping latency with iOS devices (iPad / iPhone)

Carrot 2019-03-24

pinging my iPad / iPhone shows an unreasonable high latency even if there’s no load on WiFi:

# ping 1.1.1.2
PING 1.1.1.2 (1.1.1.2) 56(84) bytes of data.
64 bytes from 1.1.1.2: icmp_seq=1 ttl=64 time=15.7 ms
64 bytes from 1.1.1.2: icmp_seq=2 ttl=64 time=42.0 ms
64 bytes from 1.1.1.2: icmp_seq=3 ttl=64 time=65.2 ms
64 bytes from 1.1.1.2: icmp_seq=4 ttl=64 time=89.4 ms

# ping 1.1.1.2

PING 1.1.1.2 (1.1.1.2) 56(84) bytes of data.

64 bytes from 1.1.1.2: icmp_seq=1 ttl=64 time=15.7 ms

64 bytes from 1.1.1.2: icmp_seq=2 ttl=64 time=42.0 ms

64 bytes from 1.1.1.2: icmp_seq=3 ttl=64 time=65.2 ms

64 bytes from 1.1.1.2: icmp_seq=4 ttl=64 time=89.4 ms

… while pinging my other devices from the iPad does show aContinue reading

Phicomm N1 (seemingly) does not support booting from raw initramfs

Carrot 2019-03-16

Even if both the documentation (in source code) and the source code of boot_get_ramdisk suggest that booti (as well as other boot* family commands) support raw initrd image, my attemptContinue reading

Boot Phicomm N1 without emmc_autoscript / s905_autoscript

Carrot 2019-03-16

It’s recommended to backup your firmware environment variables before changing them. If fw_printenv / fw_setenv does not work on your device, you might want to checkout this post to fixContinue reading

Use ext4 for /boot partition on Phicomm N1

Carrot 2019-03-06

Be careful when doing this, I suggest you backup your data before reformatting your /boot as ext4. Any mistake you make would potentially require a reflash of your device (orContinue reading

Several patches I’m using for running Linux 5.0 on Phicomm N1

Carrot 2019-03-05

meson-text-offset.patch: Patch for moving TEXT_OFFSET. This is necessary for booting Linux on Meson SoCs.

diff -uNr a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
--- a/arch/arm64/kernel/head.S  2019-01-01 00:00:00.000000000 +0000
+++ b/arch/arm64/kernel/head.S  2019-01-01 00:00:00.000000000 +0000
@@ -52,7 +52,7 @@
 #elif (PAGE_OFFSET & 0x1fffff) != 0
 #error PAGE_OFFSET must be at least 2MB aligned
 #elif TEXT_OFFSET > 0x1fffff
-#error TEXT_OFFSET must be less than 2MB
+// #error TEXT_OFFSET must be less than 2MB
 #endif

 /*
diff -uNr a/arch/arm64/Makefile b/arch/arm64/Makefile
--- a/arch/arm64/Makefile   2019-01-01 00:00:00.000000000 +0000
+++ b/arch/arm64/Makefile   2019-01-01 00:00:00.000000000 +0000
@@ -98,7 +98,7 @@
         int(2 * 1024 * 1024 / (2 ^ $(CONFIG_ARM64_PAGE_SHIFT)) * \
         rand()) * (2 ^ $(CONFIG_ARM64_PAGE_SHIFT))}")
 else
-TEXT_OFFSET := 0x00080000
+TEXT_OFFSET := 0x01080000
 endif

 ifeq ($(CONFIG_KASAN_SW_TAGS), y)

diff -uNr a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S

--- a/arch/arm64/kernel/head.S 2019-01-01 00:00:00.000000000 +0000

+++ b/arch/arm64/kernel/head.S 2019-01-01 00:00:00.000000000 +0000

@@ -52,7 +52,7 @@

#elif (PAGE_OFFSET & 0x1fffff) != 0

#error PAGE_OFFSET must be at least 2MB aligned

#elif TEXT_OFFSET > 0x1fffff

-#error TEXT_OFFSET must be less than 2MB

+// #error TEXT_OFFSET must be less than 2MB

#endif

diff -uNr a/arch/arm64/Makefile b/arch/arm64/Makefile

--- a/arch/arm64/Makefile 2019-01-01 00:00:00.000000000 +0000

+++ b/arch/arm64/Makefile 2019-01-01 00:00:00.000000000 +0000

@@ -98,7 +98,7 @@

int(2 * 1024 * 1024 / (2 ^ $(CONFIG_ARM64_PAGE_SHIFT)) * \

rand()) * (2 ^ $(CONFIG_ARM64_PAGE_SHIFT))}")

else

-TEXT_OFFSET := 0x00080000

+TEXT_OFFSET := 0x01080000

endif

ifeq ($(CONFIG_KASAN_SW_TAGS), y)

decrease-emmc-max-frequency.patch: Cap (internal) eMMC’s max-frequency. This is necessary for Phicomm N1 to boot.

diff -uNr a/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi
--- a/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi 2019-01-01 00:00:00.000000000 +0000
+++ b/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi 2019-01-01 00:00:00.000000000 +0000
@@ -202,7 +202,7 @@

    bus-width = <8>;
    cap-mmc-highspeed;
-   max-frequency = <200000000>;
+   max-frequency = <100000000>;
    non-removable;
    disable-wp;
    mmc-ddr-1_8v;

diff -uNr a/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi

--- a/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi 2019-01-01 00:00:00.000000000 +0000

+++ b/arch/arm64/boot/dts/amlogic/meson-gx-p23x-q20x.dtsi 2019-01-01 00:00:00.000000000 +0000

@@ -202,7 +202,7 @@

bus-width = <8>;

cap-mmc-highspeed;

- max-frequency = <200000000>;

+ max-frequency = <100000000>;

non-removable;

disable-wp;

mmc-ddr-1_8v;

disable-usb2-lpm.patch:Continue reading

meson-gxl-s905d-phicomm-n1.dtb in Linux 5.0 won’t boot

Carrot 2019-03-04

After diffing the working dtb and the failing one (meson-gxl-s905d-phicomm-n1.dtb from compiling the kernel by hand), the issue was found to be the incorrectly high max-frequency specified in meson-gx-p23x-q20x.dtsi: mmc@7400Continue reading

update-initramfs fails to include fsck in initrd

Carrot 2019-02-17

update-initramfs reports the following warning when generating initrd.img:

Warning: couldn't identify filesystem type for fsck hook, ignoring.

1	Warning: couldn't identify filesystem type for fsck hook, ignoring.

To identify filesystem type of /, update-initramfs requires device of / listed in /etc/fstab. My rootfs is cross-debootstrapped in virtual machine,Continue reading

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