[Android Q&A, Help & Troubleshooting] jack078:
Hi, sorry for my newbie question.

I was given a Chinese tablet from some unknown manufacturer. The settings show various fake properties (e.g. it's shown Android 8, but it's 7.0 instead), but I think I could identify some of the correct values, by using some apps and adb commands. Here is what I found (I skipped plenty of properties which looked non relevant):

130|KTE:/ # getprop
[LCM]: [feixin_boe_ili9881_wxga_40pin]
[cdma.version.baseband]: [SIXTH.CBP.MD.MP2.V71, 2017/07/24 00:01]
[gsm.project.baseband]: [JASZ6737M_65_C_N_HW(LWG_DSDS)]
[gsm.project.baseband.2]: [JASZ6737M_65_C_N_HW(LWG_DSDS)]
[gsm.version.baseband]: [MOLY.LR9.W1444.MD.LWTG.MP.V117, 2017/07/25 18:52]
[gsm.version.baseband1]: [MOLY.LR9.W1444.MD.LWTG.MP.V117, 2017/07/25 18:52]
[gsm.version.ril-impl]: [android reference-ril 1.0]
[net.perf.internal.cpu.core]: [2,2,0,0]
[net.perf.internal.cpu.freq]: [819000,819000,0,0]
[net.perf.rps.default]: [ff]
[net.perf.tether.cpu.core]: [4,4,0,0]
[net.perf.tether.cpu.freq]: [1144000,1144000,0,0]
[ro.boot.serialno]: [0123456789ABCDEF]
[ro.boot.verifiedbootstate]: [green]
[ro.bootimage.build.date]: [Wed Mar 25 20:16:25 CST 2020]
[ro.bootimage.build.date.utc]: [1585138585]
[ro.bootimage.build.fingerprint]: [Masstel/Masstel_Tab10/Masstel_Tab10:7.0/NRD90M/1501230900:user/release-keys]
[ro.bootloader]: [unknown]
[ro.bootmode]: [normal]
[ro.build.characteristics]: [tablet]
[ro.build.date]: [Wed Mar 25 20:16:25 CST 2020]
[ro.build.date.utc]: [1585138585]
[ro.build.description]: [full_kt109_53_6m_wxga-user 7.0 NRD90M 1585138601 test-keys]
[ro.build.display.id]: [ipc-M1010 pro]
[ro.build.fingerprint]: [Masstel/Masstel_Tab10/Masstel_Tab10:7.0/NRD90M/1501230900:user/release-keys]
[ro.build.flavor]: [full_kt109_53_6m_wxga-user]
[ro.build.host]: [server8]
[ro.build.id]: [NRD90M]
[ro.build.product]: [kt109_53_6m_wxga]
[ro.build.screen_size_inches]: [10.1]
[ro.build.tags]: [test-keys]
[ro.build.type]: [user]
[ro.build.user]: [user1]
[ro.build.version.all_codenames]: [REL]
[ro.build.version.base_os]: []
[ro.build.version.codename]: [REL]
[ro.build.version.incremental]: [1585138601]
[ro.build.version.preview_sdk]: [0]
[ro.build.version.release]: [8.0]
[ro.build.version.sdk]: [24]
[ro.build.version.security_patch]: [2021-01-05]
[ro.com.google.clientidbase]: [alps-full_kt109_53_6m_wxga-{country}]
[ro.com.google.clientidbase.am]: [alps-full_kt109_53_6m_wxga-{country}]
[ro.com.google.clientidbase.gmm]: [alps-full_kt109_53_6m_wxga-{country}]
[ro.com.google.clientidbase.ms]: [alps-full_kt109_53_6m_wxga-{country}]
[ro.com.google.clientidbase.yt]: [alps-full_kt109_53_6m_wxga-{country}]
[ro.com.google.gmsversion]: [7.0_r8]
[ro.hardware]: [mt6735]
[ro.have_aacencode_feature]: [1]
[ro.have_aee_feature]: [1]
[ro.jty.baseband]: [MOLY.LR9.W1444.MD.LWTG.MP.V117]
[ro.jty.baseband2]: [SIXTH.CBP.MD.MP2.V71]
[ro.jty.data.expandNum]: [1]
[ro.jty.def_launcher_cname]: []
[ro.jty.def_launcher_pname]: []
[ro.jty.display.id]: [K10_X20_FHD]
[ro.jty.fat.expandNum]: [2.4]
[ro.jty.showdev]: [true]
[ro.jty.version.release]: [ipc-M1010 pro]
[ro.kernel.zio]: [38,108,105,16]
[ro.media.maxmem]: [500000000]
[ro.mediatek.chip_ver]: [S01]
[ro.mediatek.platform]: [MT6735]
[ro.mediatek.project.path]: [device/joya_sz/kt109_53_6m_wxga]
[ro.mediatek.version.branch]: [alps-mp-n0.mp1]
[ro.mediatek.version.release]: [alps-mp-n0.mp1-V1.19_jasz6753.66.c.n]
[ro.mediatek.version.sdk]: [4]
[ro.product.board]: [KT109]
[ro.product.brand]: [Media]
[ro.product.cpu.abi]: [arm64-v8a]
[ro.product.cpu.abilist]: [arm64-v8a,armeabi-v7a,armeabi]
[ro.product.cpu.abilist32]: [armeabi-v7a,armeabi]
[ro.product.cpu.abilist64]: [arm64-v8a]
[ro.product.device]: [KTE]
[ro.product.first_api_level]: [24]
[ro.product.locale]: [en-US]
[ro.product.manufacturer]: [alps]
[ro.product.model]: [ipc-M1010 pro]
[ro.product.name]: [KTE]
[ro.recovery_id]: [0x394047a34fd8ad70049f043771ca27a65cb9bbc1000000000000000000000000]
[ro.revision]: [0]
[ro.romtool.back.picturesize]: [3264x2448]
[ro.romtool.cpu_corenumber]: [8]
[ro.romtool.cpu_frequency]: [2000]
[ro.romtool.cpu_platform]: [MT6753]
[ro.romtool.custom_build_version]: [false]
[ro.romtool.fake_lcd]: [1920x1080]
[ro.romtool.fake_memory]: [2a]
[ro.romtool.fat.name]: [ipc-M1010 pro]
[ro.romtool.fontsize]: [1]
[ro.romtool.front.picturesize]: [2560x1920]
[ro.romtool.gpu_platform]: [Mali-T720]
[ro.romtool.hlimit]: [true]
[ro.romtool.homepage]: [www.google.com]
[ro.romtool.screenbrightness]: [170]
[ro.romtool.screenofftimeout]: [60]
[ro.romtool.security_patch]: [false]
[ro.romtool.show.cpuinfo]: [MT6753 Eight 2.0GHz]
[ro.romtool.show.hardinfo]: [false]
[ro.romtool.show.lcminfo]: [1280x800]
[ro.romtool.system_update]: [false]

So it's configured to show a fake 8 cores MT6753 cpu, but it's actually a MT6735 4 cores cpu.

Then, since I don't trust that unknown (alps??) manufacturer, I'd like to flash some secure custom ROM and change the OS, maybe with Ubuntu Touch or postmarketOS, but I'm a total newbie and I don't know where to start from.

All the wiki and guides I've found assume your device is included in some list of supported brands and models, but mine is obviously not there.

How can I install a different OS on an unbranded tablet then?

Any help would be highly appreciated.