Medion Lifetab S9714 (medion-kai)

== How to enter flash mode ==
To start fastboot mode:
When tablet is running Android (with usb debugging enabled in the developer options) or recovery run
 adb reboot bootloader
To unlock bootloader in fastboot mode (CAUTION: this will erase userdata! Backup before doing this!):
 fastboot oem unlock
To boot into recovery: hold volume down and power on at the same time to start device.
== Installation ==
My procedure was:
# Backup all important user data
# Unlock bootloader (see above)
# Install CWM recovery by going into fastboot mode and then running fastboot flash recovery A2109_CWMrecovery-6.0.1.9d.img
# Backup Android installation on SD card
# Follow installation guide (note that flashing rootfs can take a few minutes without feedback, just wait)
# After flashing has finished, the screen should show the Medion logo and a notice saying "Cold booting linux"; after that, the postmarkedOS logo and then the demo should come up.
== Notes ==
Apparently, the device was manufactured by Lenovo for vendor Medion and is similar to Lenovo's A2110 / A2109 boards. Some information about the IdeaTab A2109.
== How bonsaiblue made wifi work ==
How bonsaiblue made wifi work (minus the confusing detours). Inspired by the very helpful How_drebrez_made_wifi_work.
* Find information online about the wifi chip of the device: it uses Broadcom BCM4330 for wifi 11b/g/n and Bluetooth 3.0
* Read the WiFi page, in particular the part about Broadcom WiFi.
* Since that page mentions kernel config parameters, grep for "BCM" in the devices kernel config:
 grep -i "BCM" pmaports/device/linux-medion-kai/config-medion-kai.armv7
 ...
 CONFIG_BCMDHD_FXN_FW_PATH="/system/vendor/firmware/bcm4330/fw_bcmdhd.bin"
 CONFIG_BCMDHD_FXN_NVRAM_PATH="/system/etc/nvram_4330.txt"
 CONFIG_BCMDHD_FXN_195_89=m
 ...
* So the wifi chip needs a kernel module (CONFIG_BCMDHD_FXN_195_89=m) and firmware and config files (fw_bcmdhd.bin, nvram_4330.txt).
* Download and unpack the vendor's OTA ROM zip (link in the Medion_Lifetab_S9714_(medion-kai)#See_also section). (Other ideas on how to find firmware files are on the How_to_find_device-specific_information#Firmware_files page.)
* In the unpacked ROM folder, look for system/vendor/firmware/bcm4330/fw_bcmdhd.bin and system/etc/nvram_4330.txt.
* First step is to try to get wifi to work with the vendor firmware. Later on we might be able to use existing postmarket firmware packages instead.
* Copy nvram_4330.txt to aports/device/device-medion-kai. 
* Edit device/linux-medion-kai/APKBUILD to get kernel modules built and installed:
** Increase pkgrel by one.
** At the end of the build() section, add this to build the modules:
 # the 'no-pic' flag is necessary to avoid the
 # error 'Unknown symbol _GLOBAL_OFFSET_TABLE_ (err 0)' when loading the module
 make ARCH="$_carch" CC="${CC:-gcc}" CFLAGS_MODULE="-fno-pic" \
 KBUILD_BUILD_VERSION="$((pkgrel + 1))-postmarketOS" modules
** At the end of the package() section, add this to install the modules:
 # Modules
 cd "$builddir"
 unset LDFLAGS
 make ARCH="$_carch" CC="${CC:-gcc}" \
 KBUILD_BUILD_VERSION="$((pkgrel + 1))-postmarketOS" \
 INSTALL_MOD_PATH="$pkgdir" INSTALL_MOD_STRIP=1 \
 modules_install
* Edit device/linux-medion-kai/config-medion-kai.armv7 and set the path where the wifi firmware is expected to a subfolder of /lib/firmware/postmarketos:
 CONFIG_BCMDHD_FXN_FW_PATH="/lib/firmware/postmarketos/bcmdhd/bcm4330/fw_bcm4330_bg.bin"
 CONFIG_BCMDHD_FXN_NVRAM_PATH="/lib/firmware/postmarketos/bcmdhd/bcm4330/nvram_4330.txt"
* Rebuild linux-medion-kai and create an image file:
 pmbootstrap checksum linux-medion-kai && \
 pmbootstrap kconfig check -f && \
 pmbootstrap build linux-medion-kai --force && \
 pmbootstrap install
* Chroot into the image file and check if modules have been built:
 pmbootstrap chroot -r
 
 find /lib/modules/
 
* In particular there should be /lib/modules/3.1.10/kernel/drivers/net/wireless/bcmdhd_fxn_195_89/bcmdhd.ko. Leave chroot again (with exit).
* In device/device-medion-kai, add a new file modules-load.conf and have the module found in the previous step loaded at boot time:
 # This file contains the names of kernel modules that should be loaded
 # at boot time, one per line. Lines beginning with "#" are ignored.
 # wifi module
 bcmdhd
* Edit device/device-medion-kai/APKBUILD
** Increase pkgrel by one.
** Add to source files and declare a new subpackage:
 subpackages="$pkgname-nonfree-firmware:nonfree_firmware"
 source="deviceinfo
 nvram_4330.txt
 modules-load.conf"
** At the end of the package() section, add this to put modules-load.conf in the right place on the device:
 install -Dm644 "$srcdir"/modules-load.conf \
 "$pkgdir"/etc/modules-load.d/00-$pkgname.conf
** Below the package() section, add a new nonfree_firmware() section that installs the nvram_4330.txt file from the vendor ROM.
 nonfree_firmware() {
 pkgdesc="Wifi firmware"
 mkdir "$subpkgdir"
 install -D -m644 "$srcdir"/nvram_4330.txt \
 "$subpkgdir"/lib/firmware/postmarketos/bcmdhd/bcm4330/nvram_4330.txt
 }
 
* Rebuild device-medion-kai and recreate the image file:
 pmbootstrap checksum device-medion-kai && \
 pmbootstrap build device-medion-kai --force && \
 pmbootstrap install
* Flash image to device 
 pmbootstrap flasher flash_rootfs && pmbootstrap flasher flash_kernel 
* ssh into the device via USB_Network
* Use scp to copy the firmware bin fw_bcmdhd.bin onto the device (e.g. into the /tmp directory) and move it to the path given in CONFIG_BCMDHD_FXN_FW_PATH: /lib/firmware/postmarketos/bcmdhd/bcm4330/fw_bcm4330_bg.bin, next to nvram_4330.txt, which should already be in that directory.
* Restart the device
* Log in with ssh over USB again and run lsmod to see if the kernel module has been loaded correctly:
 lsmod
 Module Size Used by
 bcmdhd 387306 0
 cfg80211 157302 1 bcmdhd
* If the module isn't listed, check that it's on the device (find /lib/modules/ -iname "*bcm*ko") and what happens if you try to insert it manually (modprobe bcmdhd || dmesg | tail -n 20). If modprobe doesn't find the module you can also try insmod /lib/modules/3.1.10/kernel/drivers/net/wireless/bcmdhd_fxn_195_89/bcmdhd.ko || dmesg | tail -n 20.If dmesg gives Unknown symbol _GLOBAL_OFFSET_TABLE_ you may be missing the -fno-pic flag when building the kernel modules.
* Once the module is loaded correctly, continue with the steps on the Wifi page:
** Check if the interface is available
 ip link
 ...
 7: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
** Turn on wifi
 nmcli radio wifi on
** Scan for available wifis:
 nmcli device wifi list ifname wlan0
** Connect to your wifi:
 nmcli device wifi connect "$SSID" password "$PASSWORD" ifname wlan0
* If wifi works, try replacing the vendor's firmware bin with bins from existing postmarket firmware packages. Information about the Broadcom firmware version is added in ASCII at the end of the blobs and can be seen with less:
 
 less fw_bcmdhd.bin
 ... 4330b2-roml/sdio-g-pool-pno-pktfilter-keepalive-wapi-wme-p2p-apsta-aoe Version: 5.90.195.89 CRC: 2303bcd6 Date: Sun 2012-07-22 19:27:22 PDT ...
* Candidate postmarket packages can be identified with grep -ril "bcm" pmaports/firmware. Package firmware-aosp-broadcom-wlan sounds promising.
* The blobs for firmware-aosp-broadcom-wlan are taken from this GitHub repository. 
* Checking blob bcm4330/fw_bcm4330_bg.bin from that repository with less shows that it's a newer version:
 less fw_bcm4330_bg.bin
 ... 4330b2-roml/sdio-g-p2p-idsup-idauth-pno Version: 5.90.195.114 CRC: 24b8f965 Date: Wed 2013-01-23 17:48:37 PST ...
* Copying fw_bcm4330_bg.bin onto the device at /lib/firmware/postmarketos/bcmdhd/bcm4330/fw_bcm4330_bg.bin and rebooting shows, that this firmware also works (with the vendor nvram_4330.txt file unchanged).
* This means we can add firmware-aosp-broadcom-wlan as a dependency in the firmware part of device/device-medion-kai/APKBUILD:
 nonfree_firmware() {
 pkgdesc="Wifi firmware"
 depends="firmware-aosp-broadcom-wlan"
 mkdir "$subpkgdir"
 install -D -m644 "$srcdir"/nvram_4330.txt \
 "$subpkgdir"/lib/firmware/postmarketos/bcmdhd/bcm4330/nvram_4330.txt
 }
Result: Merge request for wifi on medion kai
== Contributors ==
* Bonsaiblue
== Maintainer(s) ==
== Users owning this device ==
=== Related links ===
* nvram text file reference
* more recent version of broadcom firmware that also works on kai
== See also ==
* Google Nexus 7 2012 (asus-grouper)
* 
* 
* Vendor Android kernel sources in a GitHub repository
* CWM recovery is available here
* Direct link for CWM for Jelly Bean / Android 4.1
* Direct link for CWM for Ice Cream Sandwich / Android 4.0
* SuperSU-v2.46
* kernel sources for Lenovo Kai?