While analysing the issue inji/inji-wallet#523, we have observed that the PHY value is not being set somehow and that's the reason devices are getting stuck and not connecting for sharing.
Device Combination we have used to test the behaviour with and without setting the PHY :
VC sizes used :
- Small VC size - 20kb
- Large VC size - 556kb
Here with i am attaching the observations in difference in transfer speeds with and without PHY between the above two device combinations and also the average time taken for your reference.

From the above image we can see,
- Smaller VC transfer is faster without PHY.
- But for Larger VC transfer is a bit slower without PHY.
-- FYI --
While analysing the issue inji/inji-wallet#523, we have observed that the PHY value is not being set somehow and that's the reason devices are getting stuck and not connecting for sharing.
Device Combination we have used to test the behaviour with and without setting the PHY :
Samsung Tab S6 Lite -- Verifier.
Android version : 12
BLE version : 5.0
Xiaomi Mi 11X -- Wallet.
Android version : 13
BLE version : 5.1
VC sizes used :
Here with i am attaching the observations in difference in transfer speeds with and without PHY between the above two device combinations and also the average time taken for your reference.
From the above image we can see,
-- FYI --
If we are not setting the PHY, the default value for PHY is 1 - which indicates that no preference among the supported PHYs.
If we update the value for PHY, when we try to read the PHY value it will be 0 - which indicates that the corresponding parameter which was set should be used.
I am attaching the link where you can find more details on this - https://software-dl.ti.com/lprf/simplelink_cc2640r2_sdk/1.35.00.33/exports/docs/ble5stack/ble_user_guide/html/ble-stack/phy-2mbps.html#changing-phy.
I am also attaching the excel sheet link for your reference on our analysis - https://docs.google.com/spreadsheets/d/1NXFE2CuxkCPPibrvAnfOVbc9b7dXatVataXr-dkPNxk/edit#gid=1828040055