Fix P15 clone print failures (empty labels / power-off crash)#13
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Fix P15 clone print failures (empty labels / power-off crash)#13
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Pristar P15 (and likely other clones) powers off when printing because: 1. MTU notification (220) overrides the profile's packet size from 95 to 217, overwhelming the printer's application buffer. The official Marklife app forces device-specific sizes on every tick, ignoring MTU for P15 devices. 2. FlowController.reset() cleared hasRealCredits before each print job, causing starvation recovery to bypass credit-based flow control for the first few packets — even when the printer actively sends credits via CX. 3. Starvation recovery timeout was 30ms vs the official app's 1000ms, blasting packets far too aggressively when credits aren't flowing. Changes: - Cap MTU-derived packet size at profile's explicit packetSize - Preserve hasRealCredits across reset (connection property, not per-job) - Increase starvation timeout from 30ms to 1000ms to match official app
The decompiled app uses a configurable dataPacketDelay (30ms for P15 and most devices) between BLE writes. Our packetDelayMs option existed in the type but was never wired into the send loop.
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Summary
packetSize: 95but an MTU notification of 220 was overriding it to 217. Clones with smaller application-level buffers either crash (Pristar P15 powers off) or silently truncate each write, losing ~56% of image data and producing blank labels. The official Marklife app forces device-specific sizes on every tick, ignoring MTU for P15/P12 devices.hasRealCreditsacross print jobs.FlowController.reset()was clearing this flag before each job, causing starvation recovery to bypass credit-based flow control for the first few packets — even when the printer actively sends credits via CX.dataPacketDelay.Context
Reported by a user with a Pristar P15 (clone of Marklife P15). Device discovers and connects fine, but at 100% print progress the printer powers off and the frontend shows a timeout. Debug log showed
mtu=220 packet=217overriding the profile's 95-byte packet size.