[Windows Phone 7 Development and Hacking] uberamd:
Note to Samsung Focus Flash/Omnia W owners: if you're on 7.5 and get error code 80180048 "update unsuccessful" using seven-eighter, or just pushing cabs manually, here is how I fixed it:

Download all of the language packs for 7.5:

http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0404.pks_5264adfac00822e6f264444879d579fd9d83d521.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0404.pks_7419d68221a4b73171c8d57b02fa74d62047eaf6.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0405.pks_808ff53261123dfd0e86ee7ae9c63d1ed2f0809a.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0405.pks_b4ca08158f722ba8bfcd7dc6ffd8bcfc2078dbcb.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0406.pks_4b758bd9c162dbf64abaf65e5ea831a06f2e7eda.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0406.pks_8865f440166f08be5c5232f7246555b2c66606d2.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0407.pks_d89120e9719b4791ecf5f5581730952790d85505.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0407.pks_e1a132dbad341e61c902f697bbde9d2ebb98a08f.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0408.pks_d0b6fbbb0bf96899196cee43179224b2451d5c31.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0408.pks_99053859daedfb6f20eae29659254996d765b8ff.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0409.pks_ae068921fd637ba2e3e268b28e6ca1c9f3a9c11f.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0409.pks_3e940c840ee4815422610bb6da8f28ac327767cc.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_040b.pks_ce1435085bb7dfcb0453f7ff7b0fa8b8f34010eb.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_040b.pks_3bf50f7208f7fdf69932428e323a2c93bbede976.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_040c.pks_0e4fe7facb5bd169c742f7811f10e3caf4110e9a.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_040c.pks_7cbfbdf414fcea12530080f94cb7c29fea74c54a.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_040e.pks_22555d0f89f9ebbe95926056f21d8bdc24b7d520.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_040e.pks_5780cdb32b99d0adf4ff39350bddfec14a792dc5.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0410.pks_9b7013b1a94c12121b92964f6a0d12425986c195.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0410.pks_926fdca3ca7df7ac163d22b15ab18a716eef0042.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0411.pks_2123187dd97da62bcf68d06b481e1bb200d4a3ad.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0411.pks_d1b4cdb9029da5c6a25bf671de494231ec0b3e27.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0412.pks_bb4fd590e3e3ea568fba17484261d68e191bf148.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0412.pks_576bb7afb8fc4e6d89563184a8a6a5d625b449a5.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0413.pks_bd8d1a0427266b9e7a98598eb95b1f378ad9781f.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0413.pks_20bee08afa00d72fb169522f028d94fdcca87664.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0414.pks_63665eebb1733349f4454b75bf967453493ca1e5.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0414.pks_b29084e38981e548bc53419430f789077a15207c.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0415.pks_c5eae4190043d0ecc156edc363c677f685788544.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0415.pks_0613867ea56454150ce63f8b4b2612b86dfa85c3.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0416.pks_0faf0a17c2d51efe8a54f7063a56bc06537e62ee.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0416.pks_1b4634522f8f6c1792c9f85615945ed536201185.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0419.pks_a3be6ca52716096243398b5aa646825c4cd28fbe.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0419.pks_71182794a1023bec4548529ac00bbb1a5098d787.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_041d.pks_6642fcd0eb59dbd981aa1a91034df5462013d8c7.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_041d.pks_e42bb7e6d9cd9687d43cadb06c9843d7ccfe89f0.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0804.pks_26d9ffdca74b379504c2607ef260cd9d52c4add9.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0804.pks_60b681c892fd55ccab4bd2c94bdec543dd207631.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0809.pks_80abdd4c9c9f3df25432fe4465e23fc3048012cb.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0809.pks_04fcbfbd2d6f419b7f0b854da77f6ce13a16698d.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0816.pks_74bc78c410e0ea1433a3eb3aa3f71296ed8a34aa.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0816.pks_3ecb9ac90f3614c5ee80bc95c7d8f300b7de4996.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/03/diff-7.10.8107.79-7.10.8112.7-armv7-retail-microsoft.lang_0c0a.pks_69aaa5b4911d99c4669344254bfa7ba5f8cd0408.cab
http://download.windowsupdate.com/msdownload/update/software/dflt/2012/05/diff-7.10.8112.7-7.10.8773.98-armv7-retail-microsoft.lang_0c0a.pks_09cab7985d025414c9923461e0a0729d95ec6737.cab

Push them all to your device using one of the cab sending methods (I used the easy tool listed on the first post). Those should all push successfully. After that simply use Seven-Eigher, select all of the languages, and press the big Install button.

I kept getting an error and I couldn't figure out why. This ended up being the combination of steps that finally got WP7.8 on my device!