[Sony Xperia XZ2 ROMs, Kernels, Recoveries, & Other] nasko_spasko:
1. Yes it should work, but I dont have a signed zip to test it with. opengapps fail to install, but that's OK since it aint signed.

2. Yes, Internal storage works as expected. Even mounts through USB.

Bonus: I've managed to pull the log from /tmp/recovery.log. I'm trying to flash zip from sdcard: time@55 and from sideload: time@339.

$ cat ./recovery.log
[ 0.000236] Starting recovery (pid 532) on Wed May 13 03:21:42 1970
[ 0.002412] recovery filesystem table
[ 0.002427] =========================
[ 0.002438] 0 /vendor ext4 /dev/block/platform/soc/1d84000.ufshc/by-name/vendor_a 0
[ 0.002443] 1 /odm ext4 /dev/block/platform/soc/1d84000.ufshc/by-name/oem_a 0
[ 0.002447] 2 / ext4 /dev/block/bootdevice/by-name/system_a 0
[ 0.002452] 3 /odm ext4 /dev/block/bootdevice/by-name/oem_a 0
[ 0.002456] 4 /data ext4 /dev/block/bootdevice/by-name/userdata 0
[ 0.002460] 5 /persistent emmc /dev/block/bootdevice/by-name/frp 0
[ 0.002465] 6 /dsp ext4 /dev/block/bootdevice/by-name/dsp_a 0
[ 0.002469] 7 /misc emmc /dev/block/bootdevice/by-name/misc 0
[ 0.002473] 8 /firmware vfat /dev/block/bootdevice/by-name/modem_a 0
[ 0.002477] 9 /bt_firmware vfat /dev/block/bootdevice/by-name/bluetooth_a 0
[ 0.002481] 10 /persist ext4 /dev/block/bootdevice/by-name/persist 0
[ 0.002486] 11 auto auto /devices/soc/c084000.sdhci/mmc_host/mmc* 0
[ 0.002490] 12 auto auto /devices/soc/a800000.ssusb/a800000.dwc3/xhci-hcd.0.auto/usb* 0
[ 0.002494] 13 none swap /dev/block/zram0 0
[ 0.002498] 14 /tmp ramdisk ramdisk 0
[ 0.002502]
[ 0.007708] locale is [en-US]
[ 0.007720] stage is []
[ 0.007725] reason is [(null)]
[ 0.009953] W:Failed to read max brightness: No such file or directory
[ 0.009964] I:Screensaver disabled
[ 0.010668] Unknown format 875713089
[ 0.010763] Unknown format 875713089
[ 0.095069] erasing_text: en-US (137 x 57 @ 1740)
[ 0.100781] no_command_text: en-US (249 x 57 @ 1740)
[ 0.105373] error_text: en-US (99 x 57 @ 1740)
[ 0.383282] installing_text: en-US (459 x 57 @ 1740)
[ 0.389910] SELinux: Loaded file_contexts
[ 0.389945] Command: "/sbin/recovery"
[ 0.389955]
[ 0.390193] persist.camera.dc.frame.sync=0
[ 0.390206] persist.camera.eis.enable=0
[ 0.390216] persist.camera.hal.debug=0
[ 0.390226] persist.camera.kpi.debug=0
[ 0.390236] persist.camera.ois.disable=0
[ 0.390246] persist.camera.zsl.mode=1
[ 0.390256] persist.camera.dcrf.enable=0
[ 0.390267] persist.camera.dual.camera.mpo=0
[ 0.390277] persist.camera.exif.rotation=off
[ 0.390287] persist.camera.gyro.disable=1
[ 0.390298] persist.camera.lib2d.rotation=on
[ 0.390311] persist.camera.global.debug=0
[ 0.390321] persist.camera.feature.cac=0
[ 0.390418] pm.dexopt.boot=extract
[ 0.390430] pm.dexopt.ab-ota=speed-profile
[ 0.390440] pm.dexopt.shared=speed
[ 0.390451] pm.dexopt.install=quicken
[ 0.390460] pm.dexopt.inactive=verify
[ 0.390469] pm.dexopt.bg-dexopt=speed-profile
[ 0.390478] pm.dexopt.first-boot=extract
[ 0.390489] ro.qc.sdk.audio.fluencetype=fluence
[ 0.390498] ro.sf.lcd_density=480
[ 0.390509] ro.com.android.dataroaming=true
[ 0.390519] ro.nfc.port=I2C
[ 0.390529] ro.odm.expect.version=8.1.0_4.9_tama_v15
[ 0.390540] ro.qti.sdk.sensors.gestures=false
[ 0.390552] ro.qti.sensors.wu=true
[ 0.390561] ro.qti.sensors.amd=false
[ 0.390571] ro.qti.sensors.bte=false
[ 0.390580] ro.qti.sensors.cmc=false
[ 0.390590] ro.qti.sensors.dpc=false
[ 0.390600] ro.qti.sensors.fns=false
[ 0.390610] ro.qti.sensors.iod=false
[ 0.390619] ro.qti.sensors.pam=false
[ 0.390629] ro.qti.sensors.pug=false
[ 0.390638] ro.qti.sensors.qmd=false
[ 0.390648] ro.qti.sensors.rmd=false
[ 0.390657] ro.qti.sensors.smd=true
[ 0.390667] ro.qti.sensors.tap=false
[ 0.390677] ro.qti.sensors.vmd=false
[ 0.390687] ro.qti.sensors.gtap=false
[ 0.390697] ro.qti.sensors.tilt=false
[ 0.390708] ro.qti.sensors.georv=true
[ 0.390717] ro.qti.sensors.facing=false
[ 0.390727] ro.qti.sensors.laccel=true
[ 0.390736] ro.qti.sensors.qheart=false
[ 0.390746] ro.qti.sensors.rotvec=true
[ 0.390756] ro.qti.sensors.game_rv=true
[ 0.390765] ro.qti.sensors.gravity=true
[ 0.390775] ro.qti.sensors.fast_amd=false
[ 0.390785] ro.qti.sensors.als_scale=1000
[ 0.390795] ro.qti.sensors.pedometer=false
[ 0.390804] ro.qti.sensors.proximity=true
[ 0.390821] ro.qti.sensors.scrn_ortn=false
[ 0.390830] ro.qti.sensors.wrist_tilt=false
[ 0.390840] ro.qti.sensors.orientation=true
[ 0.390849] ro.qti.sensors.max_mag_rate=false
[ 0.390859] ro.qti.sensors.step_counter=true
[ 0.390868] ro.qti.sensors.max_gyro_rate=false
[ 0.390877] ro.qti.sensors.step_detector=true
[ 0.390887] ro.qti.sensors.tilt_detector=true
[ 0.390896] ro.qti.sensors.max_accel_rate=false
[ 0.390905] ro.qti.sensors.max_geomag_rotv=50
[ 0.390915] ro.usb.pid_suffix=1FA
[ 0.390926] ro.boot.vbmeta.size=3264
[ 0.390936] ro.boot.vbmeta.digest=abc366368ee0da6457a6c36696c2d12d2ddab533f7bc06f6d0fa7342fb7a5e65
[ 0.390945] ro.boot.vbmeta.hash_alg=sha256
[ 0.390955] ro.boot.vbmeta.avb_version=1.0
[ 0.390965] ro.boot.vbmeta.device_state=unlocked
[ 0.390974] ro.boot.selinux=permissive
[ 0.390983] ro.boot.baseband=sdm
[ 0.390993] ro.boot.hardware=akari
[ 0.391002] ro.boot.keymaster=1
[ 0.391012] ro.boot.bootdevice=1d84000.ufshc
[ 0.391023] ro.boot.bootloader=xboot
[ 0.391032] ro.boot.veritymode=disabled
[ 0.391041] ro.boot.slot_suffix=_a
[ 0.391050] ro.boot.verifiedbootstate=orange
[ 0.391061] ro.data.large_tcp_window_size=true
[ 0.391071] ro.hwui.path_cache_size=24
[ 0.391081] ro.hwui.layer_cache_size=32
[ 0.391090] ro.hwui.texture_cache_size=48
[ 0.391099] ro.hwui.gradient_cache_size=1
[ 0.391109] ro.hwui.r_buffer_cache_size=4
[ 0.391118] ro.hwui.drop_shadow_cache_size=5
[ 0.391129] ro.hwui.text_large_cache_width=2048
[ 0.391138] ro.hwui.text_small_cache_width=1024
[ 0.391149] ro.hwui.text_large_cache_height=1024
[ 0.391158] ro.hwui.text_small_cache_height=1024
[ 0.391167] ro.hwui.texture_cache_flushrate=0.5
[ 0.391176] ro.qcom.adreno.qgl.ShaderStorageImageExtendedFormats=0
[ 0.391187] ro.wifi.channels=
[ 0.391196] ro.wifi.addr_path=/data/vendor/wifi/wlan_mac.bin
[ 0.391206] ro.allow.mock.location=1
[ 0.391217] ro.board.platform=sdm845
[ 0.391226] ro.build.id=OPM6.171019.030.K1
[ 0.391236] ro.build.date=Sat Sep 15 00:08:49 EEST 2018
[ 0.391245] ro.build.date.utc=1536959329
[ 0.391255] ro.build.host=xeon
[ 0.391265] ro.build.tags=dev-keys
[ 0.391275] ro.build.type=eng
[ 0.391284] ro.build.user=nasko
[ 0.391294] ro.build.flavor=aosp_h8216-eng
[ 0.391304] ro.build.display.id=aosp_h8216-eng 8.1.0 OPM6.171019.030.K1 eng.nasko.20180915.000849 dev-keys
[ 0.391314] ro.build.product=akari
[ 0.391323] ro.build.version.sdk=27
[ 0.391334] ro.build.version.base_os=
[ 0.391344] ro.build.version.release=8.1.0
[ 0.391354] ro.build.version.codename=REL
[ 0.391364] ro.build.version.incremental=eng.nasko.20180915.000849
[ 0.391373] ro.build.version.preview_sdk=0
[ 0.391382] ro.build.version.all_codenames=REL
[ 0.391391] ro.build.version.security_patch=2018-09-05
[ 0.391401] ro.build.ab_update=true
[ 0.391411] ro.build.description=aosp_h8216-eng 8.1.0 OPM6.171019.030.K1 eng.nasko.20180915.000849 dev-keys
[ 0.391421] ro.build.characteristics=default
[ 0.391431] ro.build.system_root_image=true
[ 0.391441] ro.bionic.ld.warning=1
[ 0.391451] ro.kernel.android.checkjni=1
[ 0.391460] ro.secure=0
[ 0.391470] ro.treble.enabled=false
[ 0.391480] ro.vendor.build.date=Sat Sep 15 00:08:49 EEST 2018
[ 0.391490] ro.vendor.build.date.utc=1536959329
[ 0.391500] ro.vendor.build.fingerprint=Sony/aosp_h8216/akari:8.1.0/OPM6.171019.030.K1/nasko09150008:eng/dev-keys
[ 0.391510] ro.vendor.product.name=aosp_h8216
[ 0.391519] ro.vendor.product.brand=Sony
[ 0.391528] ro.vendor.product.model=Xperia XZ2 (AOSP)
[ 0.391537] ro.vendor.product.device=akari
[ 0.391547] ro.vendor.product.manufacturer=Sony
[ 0.391557] ro.vendor.extension_library=/vendor/lib/librqbalance.so
[ 0.391567] ro.zygote=zygote64_32
[ 0.391576] ro.carrier=unknown
[ 0.391586] ro.product.cpu.abi=arm64-v8a
[ 0.391596] ro.product.cpu.abilist=arm64-v8a,armeabi-v7a,armeabi
[ 0.391606] ro.product.cpu.abilist32=armeabi-v7a,armeabi
[ 0.391617] ro.product.cpu.abilist64=arm64-v8a
[ 0.391627] ro.product.name=aosp_h8216
[ 0.391636] ro.product.board=H8216
[ 0.391645] ro.product.brand=Sony
[ 0.391655] ro.product.model=Xperia XZ2 (AOSP)
[ 0.391664] ro.product.device=akari
[ 0.391674] ro.product.locale=en-US
[ 0.391684] ro.product.manufacturer=Sony
[ 0.391693] ro.baseband=sdm
[ 0.391702] ro.bootmode=unknown
[ 0.391711] ro.hardware=akari
[ 0.391721] ro.opengles.version=196610
[ 0.391730] ro.revision=0
[ 0.391740] ro.bootimage.build.date=Sat Sep 15 00:08:49 EEST 2018
[ 0.391749] ro.bootimage.build.date.utc=1536959329
[ 0.391758] ro.bootimage.build.fingerprint=Sony/aosp_h8216/akari:8.1.0/OPM6.171019.030.K1/nasko09150008:eng/dev-keys
[ 0.391768] ro.telephony.call_ring.multiple=false
[ 0.391777] ro.telephony.default_network=9
[ 0.391786] ro.bootloader=xboot
[ 0.391795] ro.debuggable=1
[ 0.391805] ro.property_service.version=2
[ 0.391814] ro.use_data_netmgrd=true
[ 0.391824] ro.qfusion_use_report_period=false
[ 0.391832] ro.control_privapp_permissions=enforce
[ 0.391842] drm.service.enabled=true
[ 0.391853] fmas.hdph_sgain=0
[ 0.391864] init.svc.adbd=running
[ 0.391872] init.svc.charger=running
[ 0.391882] init.svc.ueventd=running
[ 0.391891] init.svc.recovery=running
[ 0.391900] qcom.bluetooth.soc=cherokee
[ 0.391909] rild.libpath=/odm/lib64/libril-qc-qmi-1.so
[ 0.391919] vidc.debug.level=1
[ 0.391929] wifi.interface=wlan0
[ 0.391939] audio.deep_buffer.media=1
[ 0.391949] media.aac_51_output_enabled=true
[ 0.391958] persist.data.qmi.adb_logmask=0
[ 0.391967] persist.data.netmgrd.qos.enable=true
[ 0.391976] persist.hwc2.skip_client_color_transform=false
[ 0.391985] keyguard.no_require_sim=true
[ 0.391995] telephony.lteOnCdmaDevice=0
[ 0.392004] tombstoned.max_tombstone_count=50
[ 0.392044] sys.usb.ffs.ready=1
[ 0.392084] sys.usb.config=adb
[ 0.392171] service.adb.tcp.port=5555
[ 0.392282] ro.build.fingerprint=Sony/aosp_h8216/akari:8.1.0/OPM6.171019.030.K1/nasko09150008:eng/dev-keys
[ 0.392324] ro.boottime.adbd=3191078071
[ 0.392335] ro.boottime.init=2234
[ 0.392345] ro.boottime.init.selinux=39
[ 0.392354] ro.boottime.init.cold_boot_wait=252
[ 0.392365] ro.boottime.charger=3190092654
[ 0.392374] ro.boottime.ueventd=2924134685
[ 0.392383] ro.boottime.recovery=3190546821
[ 0.392415] ro.boot.serialno=QV701K1S1B
[ 0.392426] ro.serialno=QV701K1S1B
[ 0.392617] persist.debug.wfd.enable=1
[ 0.392628] persist.debug.sensors.hal=0
[ 0.392657] persist.audio.fluence.speaker=true
[ 0.392667] persist.audio.fluence.voicerec=false
[ 0.392676] persist.audio.fluence.voicecall=true
[ 0.392686] persist.audio.fluence.voicecomm=true
[ 0.392875] ril.subscription.types=NV,RUIM
[ 0.392887] persist.radio.oem_socket=false
[ 0.392897] persist.radio.add_power_save=1
[ 0.392906] persist.radio.apm_sim_not_pwdn=1
[ 0.393002] net.bt.name=Android
[ 0.393013] sys.usb.rndis.func.name=gsi
[ 0.393023] sys.usb.state=adb
[ 0.393033] sys.usb.controller=a600000.dwc3
[ 0.393043] persist.sys.usb.config=adb
[ 0.393052] persist.sys.wfd.virtual=0
[ 0.393062] persist.sys.dalvik.vm.lib.2=libart.so
[ 0.393098] debug.sf.latch_unsignaled=1
[ 0.393108] debug.atrace.tags.enableflags=0
[ 0.393119] debug.qualcomm.sns.hal=0
[ 0.393129] debug.qualcomm.sns.daemon=0
[ 0.393138] debug.qualcomm.sns.libsensor1=0
[ 0.393191] ro.dalvik.vm.native.bridge=0
[ 0.393203] dalvik.vm.isa.arm.variant=cortex-a9
[ 0.393214] dalvik.vm.isa.arm.features=default
[ 0.393223] dalvik.vm.isa.arm64.variant=generic
[ 0.393233] dalvik.vm.isa.arm64.features=default
[ 0.393242] dalvik.vm.dexopt.secondary=true
[ 0.393252] dalvik.vm.usejit=true
[ 0.393262] dalvik.vm.heapsize=512m
[ 0.393271] dalvik.vm.lockprof.threshold=500
[ 0.393281] dalvik.vm.dex2oat-Xms=64m
[ 0.393291] dalvik.vm.dex2oat-Xmx=512m
[ 0.393302] dalvik.vm.heapmaxfree=8m
[ 0.393311] dalvik.vm.heapminfree=512k
[ 0.393320] dalvik.vm.heapstartsize=8m
[ 0.393332] dalvik.vm.appimageformat=lz4
[ 0.393342] dalvik.vm.usejitprofiles=true
[ 0.393352] dalvik.vm.dex2oat-threads=2
[ 0.393361] dalvik.vm.heapgrowthlimit=192m
[ 0.393370] dalvik.vm.stack-trace-dir=/data/anr
[ 0.393379] dalvik.vm.image-dex2oat-Xms=64m
[ 0.393388] dalvik.vm.image-dex2oat-Xmx=64m
[ 0.393398] dalvik.vm.image-dex2oat-filter=verify-at-runtime
[ 0.393407] dalvik.vm.heaptargetutilization=0.75
[ 0.393417] dalvik.vm.image-dex2oat-threads=4
[ 0.393447] ro.config.ringtone=Ring_Synth_04.ogg
[ 0.393457] ro.config.alarm_alert=Alarm_Classic.ogg
[ 0.393467] ro.config.media_vol_steps=25
[ 0.393476] ro.config.vc_call_vol_steps=7
[ 0.393485] ro.config.notification_sound=pixiedust.ogg
[ 0.393523] ro.bt.bdaddr_path=/data/vendor/bluetooth/bluetooth_bdaddr
[ 0.393533]
[ 0.393546] Supported API: 3
[ 55.818128] E:unknown volume for path [/sdcard]
[ 55.820628]
[ 55.820639] -- Couldn't mount /sdcard.
[ 55.852837] Installation aborted.
[ 339.769955] Stopping adbd...
[ 339.780826] E:Failed to open driver control: No such file or directory
[ 339.798341] E:Failed to open driver control: No such file or directory
[ 339.814974]
[ 339.814984]
[ 339.814989] Now send the package you want to apply
[ 339.814994] to the device with "adb sideload <filename>"...
[ 351.837435] W:Failed to read /sys/class/thermal/thermal_zone73/temp: No such device
[ 351.847821] I:current maximum temperature: 125000
[ 351.859473] Finding update package...
[ 351.905742] I:Update location: /sideload/package.zip
[ 351.905759] Opening update package...
[ 351.933591] unknown fuse request opcode 2016
[ 351.933724] I:read key e=65537 hash=32
[ 351.933760] I:1 key(s) loaded from /res/keys
[ 351.933772] Verifying update package...
[ 351.978544] I:comment is 1357 bytes; signature is 1339 bytes from end
[ 359.710340] I:signature (offset: 586ff06, length: 535): 3082053106092a864886f70d010702a08205223082051e020101310b300906052b0e03021a0500300b06092a864886f70d010701a0820358308203543082023c020900c8af387b5028b9fc300d06092a864886f70d0101050500306d310b3009060355040613024555310c300a06035504080c035554433110300e06035504070c075669727475616c31133011060355040a0c0a4f70656e2047417070733111300f060355040b0c084275696c64626f743116301406035504030c0d6f70656e67617070732e6f7267301e170d3137303530353039303635365a170d3434303932303039303635365a306d310b3009060355040613024555310c300a06035504080c035554433110300e06035504070c075669727475616c31133011060355040a0c0a4f70656e2047417070733111300f060355040b0c084275696c64626f743116301406035504030c0d6f70656e67617070732e6f726730820120300d06092a864886f70d01010105000382010d00308201080282010100d6931904dec60b24b1edc762e0d9d8253e3ecd6ceb1de2ff068ca8e8bca8cd6bd3786ea70aa76ce60ebb0f993559ffd93e77a943e7e83d4b64b8e4fea2d3e656f1e267a81bbfb230b578c20443be4c7218b846f5211586f038a14e89c2be387f8ebecf8fcac3da1ee330c9ea93d0a7c3dc4af350220d50080732e0809717ee6a053359e6a694ec2cb3f284a0a466c87a94d83b31093a67372e2f6412c06e6d42f15818dffe0381cc0cd444da6cddc3b82458194801b32564134fbfde98c9287748dbf5676a540d8154c8bbca07b9e247553311c46b9af76fdeeccc8e69e7c8a2d08e782620943f99727d3c04fe72991d99df9bae38a0b2177fa31d5b6afee91f020103300d06092a864886f70d01010505000382010100d5117dc5e8b2a112c876d9ac1fab99ab699d97be31b686851a6393c011689c1ea024072d56e2f913be4e12c8b9137370ba1ee97b8577d79c57073ac967a4ffb346edcff28f503307015f31e9a4ed9cc489d642be18aa6da0da56de9042d199874cdb0e1590d73a425486785dd3e1f1962be7c29c2e1d8855cd128445a5004e56be5cf12ad18bab43c778c30d2e95213c3be4b795ab1411da59b478402230c230ffa8e4984533f84b17d6a2d3ad31cedc11fcbfee36aa5afa0d1134c1b81511a141eead3a311d4b9a91d7531c5eaace090987340e4890e32c712f5b4727ef9206f9c8a700f657e8806cbdee63c81bd984b629492af8676504242bacca69abfc40318201a13082019d020101307a306d310b3009060355040613024555310c300a06035504080c035554433110300e06035504070c075669727475616c31133011060355040a0c0a4f70656e2047417070733111300f060355040b0c084275696c64626f743116301406035504030c0d6f70656e67617070732e6f7267020900c8af387b5028b9fc300906052b0e03021a0500300d06092a864886f70d0101010500048201009b7900c6b86abcd0a6ff8b7356426a21db23dcb4f0dd3aedc7a443284ddc96f5f02260ffe3fab9e41d2b313bac16e30baedd446a29cc314f86d429d342ca2d6872e010e06ed7d9a977bf4bd545e2bedbcaf3174b235e745c14019657f2cf26e81618516007763d88e57697f1267fe187178288e90e2cc5b4fe2f0184d7bb68cd0ff844c6a83718c838e05caabc630af99412ec76e51fad725e52823dca4f31d2450acee93cc9cb7ac0d9f9e65584c404dba68b50781b53cd48fefc3c4b164b58692a55e1c9d1173800ac68c65ec926acb97b8b3e5a701cfb2e64cfc1c0aa3c85cb8ce8c70165b8fa46392736decf1292ab4898c3c98b9784b7d299cfb5a6e73f
[ 359.711293] I:failed to verify against RSA key 0
[ 359.711334] I:SHA-256 digest: 37c77bcbecd6abb29d1769a8c35ad825592e5d7c5b3f6f27e322d44a7b061b6f
[ 359.711367] E:failed to verify whole-file signature
[ 359.725357] Update package verification took 7.8 s (result 1).
[ 359.740660] E:Signature verification failed
[ 359.757118] E:error: 21
[ 359.776234] W:Failed to read /sys/class/thermal/thermal_zone73/temp: No such device
[ 359.784210] I:current maximum temperature: 125000
[ 359.784301] I:/sideload/package.zip
[ 359.784313] I:0
[ 359.784323] I:time_total: 7
[ 359.784332] I:retry: 0
[ 359.784342] I:error: 21
[ 359.784351] I:temperature_start: 125000
[ 359.784361] I:temperature_end: 125000
[ 359.784370] I:temperature_max: 125000
[ 359.784379] I:
[ 359.804986] I:initializing functionfs
[ 359.805002] I:opening control endpoint /dev/usb-ffs/adb/ep0
[ 359.805008] I:functionfs successfully initialized
[ 359.805013] I:registering usb transport
[ 359.805018] sideload-host file size 92734529 block size 65536
[ 359.805023] sideload_host finished
[ 359.806225] E:Failed to open driver control: No such file or directory
[ 359.825667] Restarting adbd...
[ 359.845301] E:Failed to open driver control: No such file or directory
[ 359.887006] Installation aborted.

---------- Post added at 03:29 PM ---------- Previous post was at 03:26 PM ----------

By the looks of it, /sdcard is not mounted at all.