I bought an unlocked Galaxy S8+ SM-G955FD from Giffgaff this week and used my old nano SIM on it - worked absolutely fine. My phone fits a single SIM only (not dual).
I kept getting prompted to update the android software on the phone though so went through with it - twice. I don't recall what version of android I was on before but I am now on version 9 - Pie. The first installation worked ok (presumbaly upgraded to Oreo), but after the latest one, my SIM isn't recognised, none of the mobile network options are available in Settings and it keeps saying "insert SIM". There is nothing wrong with the SIM as it still works on my old phone.
Also the IMEI numbers have disappeared from About Phone. Pressing *#06# in the keypad, which should also reveal them, keeps making the phone freeze.
After googling - I have literally tried everything under the sun- rebooted, re-inserted, cleaned the SIM, reset connections, rebooted and wiped cache partition, I even did a factory reset - but that did nothing - the exact same problem persists. (The factory reset retains the same android version 9).
One thing I noticed was when I boot in recovery mode (to wipe cahe partition) I see the following message at the bottom of the screen:
#fail to open recovery_cause (No such file or directory) ##report recovery cause is [unknown] #Support single-skuFile-Based OTASupported API: 3e: unknown volume for path [/ odm]e: unknown volume for path [/ vendor]
# MANUAL MODE v1.0.0#
remove failed dir ‘/system/carrier/ATT/priv-app/AttIqi_ATT’ (No such file or directory)
E: [libfs_mgr] is_dt_compatible (): firmware info was not valid : '/ proc / device-tree / firmware / android / compatible': No such file or directory
Does this mean anything relevant to the SIM and does anyone know how to fix this?