[Android Head-Units] surfer63:
Did you sign it with your own key?

From the default 1 September radio apk I did a "apktool d JY-1-C9-MUSIC-V1.0.apk", and then I did immediately an "apktool -c b JY-1-C9-MUSIC-V1.0".

This already gave an error because the "ic_point.png" was missing from "res/drawable-nodpi-v4". This is a known error so I copied the ic_point.png from the "res/drawable-land-nodpi-v4" into "res/drawable-nodpi-v4", and redid the "apktool -c b JY-1-C9-MUSIC-V1.0", followed by an "apksigner verify JY-1-C9-MUSIC-V1.0/dist/JY-1-C9-MUSIC-V1.0.apk".

This gave me:

apksigner verify JY-1-C9-Radio-V1.0/dist/JY-1-C9-Radio-V1.0.apk
DOES NOT VERIFY
ERROR: res/drawable-land-nodpi/ic_loc_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_plus_un.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq3_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_8.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq2_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bk_add_info.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bk_radio_setting.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_edit_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_point.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bk_ruler.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_ta_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_edit_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/num_bk.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_scan_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_check.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_item_remove_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_item_remove.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_band_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_item_edit_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_minus_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_save_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_btn_default_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_setting_text.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_add_freqm_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq1_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/num_bk_p.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_band_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-xxhdpi/ic_launcher.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/text_item_bg2.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_3.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freqm_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freqm_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_st_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/button_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-hdpi/ic_launcher.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_point.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_btn_add_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_0.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_add_freqp_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/list_bg.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_check_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_st_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_plus_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_dialog_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_loc_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_add_freqp_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_rds_on.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq1_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_af_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_setting_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/ic_launcher.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_item_edit.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/button_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/body_bk.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-xhdpi/ic_launcher.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_af_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_rds_off.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/bar_2.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freqp_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq4_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_dialog_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq6_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_1.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_minus_un.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bg_top.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/text_item_bg_p.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_switch_slider.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq6_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_save_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_text_bar.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq5_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_btn_default_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bitmap_bk.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/bg_bottom.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_switch_on.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/sbd_launcher_radio.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_5.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_switch_off.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_scan_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_minus_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/text_item_bg.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/bk_frame.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_af_un.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_4.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq4_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freqp_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq2_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_pty_un.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_sens_plus_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_ta_un.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_2.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_text_bar2.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_pty_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_add_freqm_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_pty_n.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_setting_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/list_layout_bg.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq3_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq_bottom.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_ta_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_launcher_radio.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-mdpi/ic_launcher.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/ic_freq5_p.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_6.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/icon_text_bar_p.9.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-land-nodpi/num_7.png entry referenced by META-INF/MANIFEST.MF not found in the APK
ERROR: res/drawable-nodpi/ic_point.png entry referenced by META-INF/MANIFEST.MF not found in the APK

Does this give the same result for you?

I'm on GalliumOS, which is an ubuntu derivative for chromebooks with a modified/hacked bios firmware.

apktool is from the default ubuntu repositories